National University of San Luis

About: National University of San Luis is a education organization based out in San Luis, Argentina. It is known for research contribution in the topics: Adsorption & Monte Carlo method. The organization has 2451 authors who have published 4459 publications receiving 67704 citations. The organization is also known as: UNSL.

Trading water for carbon with biological carbon sequestration

Abstract: Carbon sequestration strategies highlight tree plantations without considering their full environmental consequences. We combined field research, synthesis of more than 600 observations, and climate and economic modeling to document substantial losses in stream flow, and increased soil salinization and acidification, with afforestation. Plantations decreased stream flow by 227 millimeters per year globally (52%), with 13% of streams drying completely for at least 1 year. Regional modeling of U.S. plantation scenarios suggests that climate feedbacks are unlikely to offset such water losses and could exacerbate them. Plantations can help control groundwater recharge and upwelling but reduce stream flow and salinize and acidify some soils.

Effects of afforestation on water yield: a global synthesis with implications for policy

Abstract: Carbon sequestration programs, including afforestation and reforestation, are gaining attention globally and will alter many ecosystem processes, including water yield Some previous analyses have addressed deforestation and water yield, while the effects of afforestation on water yield have been considered for some regions However, to our knowledge no systematic global analysis of the effects of afforestation on water yield has been undertaken To assess and predict these effects globally, we analyzed 26 catchment data sets with 504 observations, including annual runoff and low flow We examined changes in the context of several variables, including original vegetation type, plantation species, plantation age, and mean annual precipitation (MAP) All of these variables should be useful for understanding and modeling the effects of afforestation on water yield We found that annual runoff was reduced on average by 44% (±3%) and 31% (±2%) when grasslands and shrublands were afforested, respectively Eucalypts had a larger impact than other tree species in afforested grasslands (P=0002), reducing runoff (90) by 75% (±10%), compared with a 40% (±3%) average decrease with pines Runoff losses increased significantly with plantation age for at least 20 years after planting, whether expressed as absolute changes (mm) or as a proportion of predicted runoff (%) (P<0001) For grasslands, absolute reductions in annual runoff were greatest at wetter sites, but proportional reductions were significantly larger in drier sites (P<001 and P<0001, respectively) Afforestation effects on low flow were similar to those on total annual flow, but proportional reductions were even larger for low flow (P<0001) These results clearly demonstrate that reductions in runoff can be expected following afforestation of grasslands and shrublands and may be most severe in drier regions Our results suggest that, in a region where natural runoff is less than 10% of MAP, afforestation should result in a complete loss of runoff; where natural runoff is 30% of precipitation, it will likely be cut by half or more when trees are planted The possibility that afforestation could cause or intensify water shortages in many locations is a tradeoff that should be explicitly addressed in carbon sequestration programs

Anti-inflammatory properties of plant flavonoids. Effects of rutin, quercetin and hesperidin on adjuvant arthritis in rat.

Abstract: The anti-inflammatory activities of three flavonoids were investigated in rats using the Mizushima et al. model of acute and chronic inflammation. Intraperitoneal administration of rutin, quercetin (flavonols) and hesperidin (flavanone), given at daily doses equivalent to 80 mg/kg, inhibited both acute and chronic phases of this experimental model of inflammation. Rutin was the most active in the chronic phase.

Hydrologic regulation of plant rooting depth

Abstract: Plant rooting depth affects ecosystem resilience to environmental stress such as drought. Deep roots connect deep soil/groundwater to the atmosphere, thus influencing the hydrologic cycle and climate. Deep roots enhance bedrock weathering, thus regulating the long-term carbon cycle. However, we know little about how deep roots go and why. Here, we present a global synthesis of 2,200 root observations of >1,000 species along biotic (life form, genus) and abiotic (precipitation, soil, drainage) gradients. Results reveal strong sensitivities of rooting depth to local soil water profiles determined by precipitation infiltration depth from the top (reflecting climate and soil), and groundwater table depth from below (reflecting topography-driven land drainage). In well-drained uplands, rooting depth follows infiltration depth; in waterlogged lowlands, roots stay shallow, avoiding oxygen stress below the water table; in between, high productivity and drought can send roots many meters down to the groundwater capillary fringe. This framework explains the contrasting rooting depths observed under the same climate for the same species but at distinct topographic positions. We assess the global significance of these hydrologic mechanisms by estimating root water-uptake depths using an inverse model, based on observed productivity and atmosphere, at 30″ (∼1-km) global grids to capture the topography critical to soil hydrology. The resulting patterns of plant rooting depth bear a strong topographic and hydrologic signature at landscape to global scales. They underscore a fundamental plant–water feedback pathway that may be critical to understanding plant-mediated global change.

Do LoRa Low-Power Wide-Area Networks Scale?

Abstract: New Internet of Things (IoT) technologies such as Long Range (LoRa) are emerging which enable power efficient wireless communication over very long distances. Devices typically communicate directly to a sink node which removes the need of constructing and maintaining a complex multi-hop network. Given the fact that a wide area is covered and that all devices communicate directly to a few sink nodes a large number of nodes have to share the communication medium. LoRa provides for this reason a range of communication options (centre frequency, spreading factor, bandwidth, coding rates) from which a transmitter can choose. Many combination settings are orthogonal and provide simultaneous collision free communications. Nevertheless, there is a limit regarding the number of transmitters a LoRa system can support. In this paper we investigate the capacity limits of LoRa networks. Using experiments we develop models describing LoRa communication behaviour. We use these models to parameterise a LoRa simulation to study scalability. Our experiments show that a typical smart city deployment can support 120 nodes per 3.8 ha, which is not sufficient for future IoT deployments. LoRa networks can scale quite well, however, if they use dynamic communication parameter selection and/or multiple sinks.