Soil water content effects on net ecosystem CO2 exchange and actual evapotranspiration in a Mediterranean semiarid savanna of Central Chile

Biosphere-atmosphere water and carbon fluxes depend on ecosystem structure, and their magnitudes and seasonal behavior are driven by environmental and biological factors. We studied the seasonal behavior of net ecosystem CO2 exchange (NEE), Gross Primary Productivity (GPP), Ecosystem Respiration (RE), and actual evapotranspiration (ETa) obtained by eddy covariance measurements during two years in a Mediterranean Acacia savanna ecosystem (Acacia caven) in Central Chile. The annual carbon balance was −53 g C m−2 in 2011 and −111 g C m−2 in 2012, showing that the ecosystem acts as a net sink of CO2, notwithstanding water limitations on photosynthesis observed in this particularly dry period. Total annual ETa was of 128 mm in 2011 and 139 mm in 2012. Both NEE and ETa exhibited strong seasonality with peak values recorded in the winter season (July to September), as a result of ecosystem phenology, soil water content and rainfall occurrence. Consequently, the maximum carbon assimilation rate occurred in wintertime. Results show that soil water content is a major driver of GPP and RE, defining their seasonal patterns and the annual carbon assimilation capacity of the ecosystem, and also modulating the effect that solar radiation and air temperature have on NEE components at shorter time scales.This work was funded by FONDECYT projects 1120713 and 1170429, a grant from the Inter-American Institute for Global Change Research (IAI) [grant number CRN3056], which is supported by the US National Science Foundation [grant number GEO-1128040], and the Spanish Ministry of Economy and Competitiveness project GEI Spain (CGL2014-52838-C2-1-R), including ERDF founds. F. Bravo-Martínez is grateful to CONICYT for the grants “Formación de Capital Humano Avanzado-2009′′, “Beca de Apoyo al término de la tesis doctoral-2012′′, and CORFO INNOVA Grant N° 09CN14-5704. We thank to Enrique Pérez Sanchez-Cañete and Borja Ruíz- Reverter for technical support. We also thank “CODELCO–División Andina” for use of the site. C. Montes acknowledges the NASA Postdoctoral Program and to Universities Space Research Association

An IT Project Management Methodology Generator Based on an Agile Project Management Process Framework

Information Technology Project Management and Software Project Management in particular depends heavily on the project’s type and constraints. Quality, financial, technical, schedule, complexity and other constraints affect significantly the management process. Over the last two decades project management methodologies have been developed to support the project management effort. Many methodologies cover generic approaches emphasizing on the planning or estimation activities, others on tracking, others on quality and others on very specific management practices that could support the delivery of very specific projects. This paper introduces an adjustable (agile) project management framework for managing information technology projects of any type. The framework divides the management activities into systems engineering management and systems acquisitions management phases and operates as a methodology generator feed by the project constraints. The project management methodology that derives is a combination of management and engineering phases based on the needs and constraints of each project per case

Speciation of Cr, Cu, Ni and Zn in soils irrigated with contaminated waters: A case study of agricultural soils from the plain of Saiss (Fez, Morocco)

The excessive input of heavy metals into agricultural soils has become one of the most important concerns in the third world cities all over the world. The contamination of agricultural soils can affect the health of people living in agricultural areas and the surrounding ecosystems. The current study was conducted to assess the quality of urban and suburban soils of the City of Fez (Morocco), which are irrigated by waters enriched by heavy metals. The main objective was to define the distribution and the mobility of heavy metals in different soil compartments using the method of sequential extractions. The samples were also investigated for mineralogy using X-ray diffraction. The identified minerals were mainly composed of quartz, carbonate and clay minerals. Smectite and mixed-layer (chlorite-vermiculite and mica-smectite) are by far the most abundant clay minerals in all soils. The study of the availability and distribution of heavy metals (Cr, Cu, Ni, Pb and Zn) in urban soils, allowed us to observe a total content of Cr in the Oued Fez soils which is lower than the contents in the Oued Sebou soils. The Cu and Zn contents are low in Oued Sebou. Despite the Oued Fez input; the contents of these elements in the confluence do not increase. Sequential extractions completed the study of the potential mobility of heavy metals in different fractions of the soil. Indeed, this has allowed us to show that Cr, Cu, Ni and Pb are mostly related to the residual fraction; they are therefore theoretically little mobile; while Zn is practically related to the metals oxides fraction and exchangeable phase, respectively, in soils (FEZ1, FEZ2, SEBup) and (SEBdown, SEBconf), therefore the Zn is potentially mobile