Search results for "GRAS"
showing 10 items of 727 documents
Arc crossing minimization in graphs with GRASP
2001
Graphs are commonly used to represent information in many fields of science and engineering. Automatic drawing tools generate comprehensible graphs from data, taking into account a variety of properties, enabling users to see important relationships in the data. The goal of limiting the number of arc crossings is a well-admitted criterion for a good drawing. In this paper, we present a Greedy Randomized Adaptive Search Procedure (GRASP) for the problem of minimizing arc crossings in graphs. Computational experiments with 200 graphs with up to 350 vertices are presented to assess the merit of the method. We show that simple heuristics are very fast but result in inferior solutions, while hig…
High emissions of greenhouse gases from grasslands on peat and other organic soils
2016
Drainage has turned peatlands from a carbon sink into one of the world's largest greenhouse gas (GHG) sources from cultivated soils. We analyzed a unique data set (12 peatlands, 48 sites and 122 annual budgets) of mainly unpublished GHG emissions from grasslands on bog and fen peat as well as other soils rich in soil organic carbon (SOC) in Germany. Emissions and environmental variables were measured with identical methods. Site-averaged GHG budgets were surprisingly variable (29.2 ± 17.4 t CO2 -eq. ha-1 yr-1 ) and partially higher than all published data and the IPCC default emission factors for GHG inventories. Generally, CO2 (27.7 ± 17.3 t CO2 ha-1 yr-1 ) dominated the GHG budget. Nit…
Influence of fat mass for the VO2max and ventilatory thresholds in young athletes of endurance sport specialties
2016
[Resumen] El objetivo del estudio es analizar la influencia de la masa grasa total y su % respecto al peso corporal total, así como la masa grasa regionalizada (Σ pliegues tronco, Σ pliegues abdomen, cociente TS/TI, phantom (Ph) de los pliegues) y su % respecto a la masa grasa total, en relación al VO2max y los Umbrales Ventilatorios (VT1 y VT2) en jóvenes deportistas en función de su especialidad deportiva y grupo de edad. La muestra está compuesta por 400 deportistas de ambos sexos del Centro de Tecnificación de Cheste (Valencia) clasificados en 3 grupos de edad: 0,05) entre atletismo y natación. Para el caso de los grupos de edad se han encontrado diferencias significativas (p0,05) entre…
Recognising a hand by grasp.
2000
The present study aimed to demonstrate that motor representations are used to recognise biological stimuli. In three experiments subjects were required to judge laterality of hands and forearms presented by pictures. The postures of the hands were those assumed when holding a small, medium and large sphere. In experiment 1, the sphere held in hand was presented, whereas in experiment 2 it was absent. In experiment 3, the same images, showing holding-a-sphere hands, as in experiment 1 were presented, but without forearm. In all experiments one finger of each hand could be absent. In experiment 1 recognition time was longer for those hand postures for which the corresponding grasping motor ac…
Daurian pikas ( Ochotona daurica ) and grassland condition in eastern Mongolia
2003
Pikas ( Ochotona spp.) are burrowing herbivorous mammals believed to play a keystone role in determining the biodiversity of steppe ecosystems. Impacts of domestic livestock grazing on the distribution and abundance of the Daurian pika Ochotona daurica were investigated in eastern Mongolia where the species is widespread and abundant. Effects of pikas on plant species richness and vegetation coverage were examined at different distances from burrow systems. Daurian pikas were nearly absent from severely grazed study sites, and incidence of the species increased with decreasing grazing intensity. The number of occupied burrow systems and usage of burrows was higher in sites with lower grazin…
Dimensional interpolation and the Selberg integral
2019
Abstract We show that a version of dimensional interpolation for the Riemann–Roch–Hirzebruch formalism in the case of a grassmannian leads to an expression for the Euler characteristic of line bundles in terms of a Selberg integral. We propose a way to interpolate higher Bessel equations, their wedge powers, and monodromies thereof to non–integer orders, and link the result with the dimensional interpolation of the RRH formalism in the spirit of the gamma conjectures.
The discovery of stapes
2013
Giovanni Filippo Ingrassia revisited and redefined some of Galeno's reports, and was recognized as one of the leading Italian Physicians of the 16th century. Ingrassia principally studied the skull, and gave very important contributions to otorhinolaryngology, including the discovery of the stapes. He also isolated the inferior nasal concha from the maxillary bone, described the frontal sinus, the pterygopalatine fossa and several foramina of the skull. Ingrassia firstly attributed a sensorial function to the middle ear bones, which he called fifth particular function. He also added some details to the description of the VIII cranial nerve, which introduces the concept of bone conducting so…
Frequent coinfection of cells explains functional in vivo complementation between cytomegalovirus variants in the multiply infected host.
2005
In contrast to many other virus infections, primary cytomegalovirus (CMV) infection does not fully protect against reinfection. Accordingly, clinical data have revealed a coexistence of multiple human CMV variants/ strains in individual patients. Notably, the phenomenon of multiple infection was found to correlate with increased virus load and severity of CMV disease. Although of obvious medical relevance, the mechanism underlying this correlation is unknown. A weak immune response in an individual could be responsible for a more severe disease and for multiple infections. Alternatively, synergistic contributions of variants that differ in their biological properties can lead to qualitative…
Predatory habits of the grasshopper-hunting waspStizus continuus(Hymenoptera: Crabronidae): diet preference, predator–prey size relationships and for…
2009
In a coastal salt-marsh of Spain, the digger wasp Stizus continuus primarily hunted for grasshoppers of the genus Heteracris, revealing (at least in the period of the study and in this area) this wasp to be almost monophagous. In contrast, grasshoppers of the genus Acrotylus were ignored by the wasps in spite of their high abundance in the environment. We hypothesize that this bias occurred because Acrotylus is found more often on the soil and on grasses, while Heteracris is nearly only found on Sarcocornia bushes, which probably represent the habitat mostly exploited by the wasps for hunting. The greater variance in size of the prey collected by larger females produced weak wasp–prey size …
Flux heterogeneity and evapotranspiration partitioning in a sparse canopy: the fallow savanna
1997
Abstract This paper focuses on in situ measurements obtained during the intensive observation period of the HAPEX-Sahel experiment. Micrometeorological measurements and trunk sap flow monitoring were combined to analyse transfer characteristics of a fallow savanna site within the East Central Supersite. Results show that the shrub canopy heterogeneity induces a large spatial variability of solar irradiance, soil heat flux and sensible and latent heat fluxes at the grassland level. This variability is induced by both a “shade effect” and a “wake effect”. Both shrubs and grassland provide sources of vapour, but the partitioning of evapotranspiration between these two components varies conside…