213 research outputs found
Relationship of Soil to Native Pasture in a Flooding Pampa Area (Argentine)
The influence of the topography in soils found in the area surrounding the Chascomús lagoon is examined. The study of the profiles within the representative transect in each microenvironment reveals changes related to its traits. Its relationship with the vegetation present in each toposequence position was observed. The worsening of the natural drainage conditions, are related to reduction of organic matter, increase in the values of pH and PSI, greater intensity of hydromorphic traces and appearance of groups of characteristic species
Root Distribution Study of Forage Gramina Under Conservation Tillage Systems, By a Tracer Technique
The aim of this work is to evaluate the root activity patterns of three forage graminaceous species under different tillage systems. The field experiment was carried out during 1993-94 in a Mollisol under three tillage systems: plowing, chiseling tillage and subsoiling tillage system cultivated with Lolium multiflorum, Bromus catharticus and Phalaris aquatica. Significant differences were found in lateral root distribution between tillage systems. Subsoiling tillage system treatment showed the largest presence of roots at 10 cm lateral distance from the plants. No differences in root activity at 10, 20, and 30 cm from the plant were found in chiseling tillage treatment. Plowing treatment showed a higher root activity in the first 20 cm from the plant. The total root activity was the highest in subsoiling treatment and significantly different from chiseling and plowing tillage systems
Tidal sands as biogeochemical reactors
Sandy sediments of continental shelves and most beaches are often thought of as geochemical deserts because they are usually poor in organic matter and other reactive substances. The present study focuses on analyses of dissolved biogenic compounds of surface seawater and pore waters of Aquitanian coastal beach sediments. To quantitatively assess the biogeochemical reactions, we collected pore waters at low tide on tidal cross-shore transects unaffected by freshwater inputs. We recorded temperature, salinity, oxygen saturation state, and nutrient concentrations. These parameters were compared to the values recorded in the seawater entering the interstitial environment during floods. Cross-shore topography and position of piezometric level at low tide were obtained from kinematics GPS records. Residence time of pore waters was estimated by a tracer approach, using dissolved silica concentration and kinetics estimate of quartz dissolution with seawater. Kinetics parameters were based on dissolved silica concentration monitoring during 20-day incubations of sediment with seawater. We found that seawater that entered the sediment during flood tides remained up to seven tidal cycles within the interstitial environment. Oxygen saturation of seawater was close to 100%, whereas it was as low as 80% in pore waters. Concentrations of dissolved nutrients were higher in pore waters than in seawater. These results suggest that aerobic respiration occurred in the sands. We propose that mineralised organic matter originated from planktonic material that infiltrated the sediment with water during flood tides. Therefore, the sandy tidal sediment of the Aquitanian coast is a biogeochemical reactor that promotes or accelerates remineralisation of coastal pelagic primary production. Mass balance calculations suggest that this single process supplies about 37 kmol of nitrate and 1.9 kmol of dissolved inorganic phosphorus (DIP) to the 250-km long Aquitanian coast during each semi-diurnal tidal cycle. It represents about 1.5% of nitrate and 5% of DIP supplied by the nearest estuary
Modelling stand biomass fractions in Galician Eucalyptus globulus plantations by use of different LiDAR pulse densities
Aims of study: To evaluate the potential use of canopy height and intensity distributions, determined by airborne
LiDAR, for the estimation of crown, stem and aboveground biomass fractions.
To assess the effects of a reduction in LiDAR pulse densities on model precision.
Area of study: The study area is located in Galicia, NW Spain. The forests are representative of Eucalyptus globulus
stands in NW Spain, characterized by low-intensity silvicultural treatments and by the presence of tall shrub.
Material and methods: Linear, multiplicative power and exponential models were used to establish empirical
relationships between field measurements and LiDAR metrics.
A random selection of LiDAR returns and a comparison of the prediction errors by LiDAR pulse density factor
were performed to study a possible loss of fit in these models.
Main results: Models showed similar goodness-of-fit statistics to those reported in the international literature. R2
ranged from 0.52 to 0.75 for stand crown biomass, from 0.64 to 0.87 for stand stem biomass, and from 0.63 to 0.86
for stand aboveground biomass. The RMSE/MEAN · 100 of the set of fitted models ranged from 17.4% to 28.4%.
Models precision was essentially maintained when 87.5% of the original point cloud was reduced, i.e. a reduction
from 4 pulses m–2 to 0.5 pulses m–2.
Research highlights: Considering the results of this study, the low-density LiDAR data that are released by the
Spanish National Geographic Institute will be an excellent source of information for reducing the cost of forest
inventories
Plant responses to fertilization experiments in lowland, species-rich, tropical forests.
We present a meta-analysis of plant responses to fertilization experiments conducted in lowland, species-rich, tropical forests. We also update a key result and present the first species-level analyses of tree growth rates for a 15-yr factorial nitrogen (N), phosphorus (P), and potassium (K) experiment conducted in central Panama. The update concerns community-level tree growth rates, which responded significantly to the addition of N and K together after 10 yr of fertilization but not after 15 yr. Our experimental soils are infertile for the region, and species whose regional distributions are strongly associated with low soil P availability dominate the local tree flora. Under these circumstances, we expect muted responses to fertilization, and we predicted species associated with low-P soils would respond most slowly. The data did not support this prediction, species-level tree growth responses to P addition were unrelated to species-level soil P associations. The meta-analysis demonstrated that nutrient limitation is widespread in lowland tropical forests and evaluated two directional hypotheses concerning plant responses to N addition and to P addition. The meta-analysis supported the hypothesis that tree (or biomass) growth rate responses to fertilization are weaker in old growth forests and stronger in secondary forests, where rapid biomass accumulation provides a nutrient sink. The meta-analysis found no support for the long-standing hypothesis that plant responses are stronger for P addition and weaker for N addition. We do not advocate discarding the latter hypothesis. There are only 14 fertilization experiments from lowland, species-rich, tropical forests, 13 of the 14 experiments added nutrients for five or fewer years, and responses vary widely among experiments. Potential fertilization responses should be muted when the species present are well adapted to nutrient-poor soils, as is the case in our experiment, and when pest pressure increases with fertilization, as it does in our experiment. The statistical power and especially the duration of fertilization experiments conducted in old growth, tropical forests might be insufficient to detect the slow, modest growth responses that are to be expected
Backtracking NOM1::ETV6 fusion to neonatal pathogenesis of t(7;12) (q36;p13) infant AML
This research was partially supported by a donation from the patient\u2019s family and Heroga Fertilizantes. Research in PM\u2019s laboratory is supported by CERCA/Generalitat de Catalunya and Fundaci\u00F3 Josep Carreras-Obra Social la Caixa for core support, the European Research Council grants (ERC-PoC-957466, ERC-PoC-101100665), the H2020 EU program (101057250-CANCERNA), the MINECO (PID2022-142966OB-I00/ MCIN/AEI/10.13039/501100011033 and Feder Funds), the MINECO/European Union NextGenerationEU (CPP2021-008508, CPP2022-009759); the Deutsche Jos\u00E9 Carreras Leuk\u00E4mie-Stiftung (DJCLS15R/2021 and DJCLS 02R/2023), the Spanish Association Against Cancer (AECC, PRYGN234975MENE) and the ISCIII-RICORS within the Next Generation EU program (plan de Recuperaci\u00F3n, Transformaci\u00F3n y Resilencia). Research in XSP\u2019s laboratory is supported by Ministerio de Ciencia e Innovaci\u00F3n (PID2020-117185RB-I00); the Spanish Association Against Cancer (AECC); Centro de Investigaci\u00F3n Biom\u00E9dica en Red C\u00E1ncer (CIBERONC); \u201CLa Caixa\u201D Foundation CLLSYSTEMS (HR22-00172), European Union NextGenerationEU/Mecanismo para la Recuperaci\u00F3n y la Resilencia (MRR)/PRTR and the Instituto de Salud Carlos III (ISCIII) (PMP21/00015). OM and TV-H were supported by an investigator award from AECC (INVES211226MOLI and INVES223069VELA, respectively)
LIGHTNESS: a function-virtualizable software defined data center network with all-optical circuit/packet switching
©2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Modern high-performance data centers are responsible for delivering a huge variety of cloud applications to the end-users, which are increasingly pushing the limits of the currently deployed computing and network infrastructure. All-optical dynamic data center network (DCN) architectures are strong candidates to overcome those adversities, especially when they are combined with an intelligent software defined control plane. In this paper, we report the first harmonious integration of an optical flexible hardware framework operated by an agile software and virtualization platform. The LIGHTNESS deeply programmable all-optical circuit and packet switched data plane is able to perform unicast/multicast switch-over on-demand, while the powerful software defined networking (SDN) control plane enables the virtualization of computing and network resources creating a virtual data center and virtual network functions (VNF) on top of the data plane. We experimentally demonstrate realistic intra DCN with deterministic latencies for both unicast and multicast, showcasing monitoring, and database migration scenarios each of which is enabled by an associated network function virtualization element. Results demonstrate a fully functional complete unification of an advanced optical data plane with an SDN control plane, promising more efficient management of the next-generation data center compute and network resources.Peer ReviewedPostprint (author's final draft
Development and experimentation towards a multicast-enabled Internet
In this paper, we report our development experience and experimentation studies of two multicast routing schemes for the Internet, namely, PIM-SSM and GCMR. We detail their implementation over the Quagga open source routing suite, as well as their experimentation tests over a large-scale topology that reproduces the Internet characteristics
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