Long term trends in fertility of soils under continuous cultivation and cereal cropping in southern Queensland. I. Overall changes in soil properties and trends in winter cereal yields

Changes in fertility of some southern Queensland soils resulting from extended periods of cultivation are presented, together with trends in yields of winter cereals on these soils. Six major soils of the cereal-belt, cropped for maximum periods of 20-70 years were examined. These were: Black earths, Waco soil; grey, brown and red clays (brigalow), Langlands-Logie soil; grey, brown and red clays (poplar box), Cecilvale soil; grey, brown and red clays (belah), Billa Billa soil; grey, brown and red clays (coolibah), Thallon soil; red earths, Riverview soil. Organic matter and its constituents, especially total organic C, organic C in the light fraction, total N and mineralizable N, were affected most by cultivation, showing decreases of 19-67% overall. Other soil properties probably associated with organic matter, including bulk density and DTPA (diethylenetriaminepentaacetic acid) extractable manganese, were also significantly affected by cultivation in all soils. Soil properties affected least by cultivation were concentrations of inorganic phosphorus, total and exchangeable potassium, calcium carbonate, and dithionite extractable iron and aluminium. Most other soil properties studied (organic P, total sulfur, pH, exchangeable magnesium and sodium, exchangeable sodium percentage, and oxalate-extractable iron and aluminium) were affected by cultivation in at least four soils. Four factors accounted for 70% of the total variation among the 45 soil properties considered. They appeared to represent organic matter, clay colloids, iron and aluminium oxides, and soluble salts. Dry matter yield and/or N uptake of winter cereal crops (wheat and barley) measured in 1983 showed significant decreasing trends with period of cultivation in all soils

Nucleophilicity of Glutathione: A Link to Michael Acceptor Reactivities

Deprotonated glutathione is among the most potent biological nucleophiles and plays an important physiological role in cellular detoxification by forming covalent conjugates with Michael acceptors. The electrophilicity E of various Michael acceptors was characterized recently according to the Patz–Mayr relation lg k2=sN(N+E). We now determined the nucleophilic reactivity (N, sN) of glutathione (GSH) in aqueous solution at 20 °C to connect published GSH reactivities (kGSH) with Mayr's electrophilicity scale (E). In this way, electrophilicities E of more than 70 Michael acceptors could be estimated, which can now be used to systematically predict novel reactions with the multitude of nucleophiles whose nucleophilicity parameters N/sN are known

Availability to ruminants of nitrogen in senesced C4 tropical grasses

Context: Nutritional standards usually assume that ∼10% of the total nitrogen (TN) in forages is indigestible and hence not available to the ruminant. Senesced tropical C4 grasses often contain TN concentrations that are marginal or deficient to meet the nutrient requirements of ruminants, and low TN availability will exacerbate N deficiencies.Aim: The aim of the study was to estimate the availability (i.e. digestibility) to ruminants of TN in mature and senesced C4 grasses, using data derived from previous experiments and published data.Methods: In Dataset 1, forages grown in subtropical or tropical environments, including C4 (n = 143) and C3 (n = 15) grasses, were analysed for parameters including TN, acid detergent fibre (ADF), and N insoluble in ADF solution (ADIN). ADIN was used as a measure of unavailable TN. The Dataset 2 analysis included published measurements of TN and ADIN in C4 (n = 187) and C3 (n = 45) grasses.Key results: In Dataset 1, TN averaged 9.7 and ADIN 1.45 g N/kg diet DM in C4 grasses. ADIN concentration could be predicted from TN and ADF concentrations by multiple regression (R2 = 0.50; P 400 and >500 g ADF/kg DM, ADIN/TN averaged 190 and 230 g/kg, respectively, and in those containing 400 g ADF, <10 g TN or <530 g digestible DM/kg, the proportion of TN available to ruminants is substantially lower than that assumed for forages in general.Implications: Low availability of TN in many senesced C4 grasses needs to be considered when evaluating the adequacy of dietary TN for ruminants grazing senesced tropical grass pastures

Teaching Spatial Data Analysis: A Case Study with Recommendations

Learning from data is a valuable skill for nonprofit professionals and researchers. Often, data have a spatial component, and data relevant to the nonprofit sector are no exception. Understanding spatial aspects of the nonprofit sector may provide immense value to social entrepreneurs, funders, and policy makers, by guiding programmatic decisions, facilitating resource allocation, and development policy. As a result, spatial thinking has become an essential component of critical thinking and decision making among nonprofit professionals. The goal of this case study is to support and encourage instruction of spatial data analysis and spatial thinking in nonprofit studies. The case study presents a local nonprofit data set, along with open data and code, to assist the instructors teaching spatial aspects of the nonprofit sector. Pedagogical approaches are discussed

Exploring Niche Alteration in Nonprofit Organizations

The organizational niche is a concept integral to organizational ecology, reflecting an organization’s mission, expertise, capacity, and resource requirements. The choice of niche is crucial to the viability of the organization; however, the reasons organizations alter their niche are poorly understood. We hypothesize that nonprofit organizations alter their niche to reduce environmental pressure and gain access to resources. The results indicate that niche alteration predicts increases in total revenue with average increases in revenue from program services and contributions (depending on the measure). Additionally, nonprofits that are younger, larger, and have more concentrated revenue, are more likely to alter their niche

Διευρύνοντας το Μεθοδολογικό πλάισιο των Ολοκληρωμένων Μοντέλων Χρήσεων-Γης και Μεταφορών: Χωρικά Οικονομετρικά Μοντέλα και Αξιολόγηση Πολιτικών

323 σ.Στην παρούσα εργασία εξετάζεται η διεύρυνση του μεθοδολογικού πλαισίου των Όλοκληρωμένων Μοντέλων Χρήσεων-Γης και Μεταφορών σε κάθε επίπεδο. Οι προτεινόμενες βελτιώσεις αποσκοπούν στην αύξηση των ικανοτήτων πρόβλεψης, αξιοποιώντας τα οφέλη της μικροπροσομοίωσης σε τρείς διαστάσεις, άτομο, χώρο και χρόνο, με σκοπό να καταστόύν τα μοντέλα αυτά ευέλικτα εργαλεία αξιολοόγησης πολιτικών.In this research, the methodological framework of the Integrated Land-Use and Transport (LUTI) models is extended at every level. The objective of developing and implementing LUTI models is to predict the direct and indirect impacts of –transport and land-use– policies, on the environment, the society and the economy. The proposed improvements aim to increase the predicting capabilities of the current LUTI models, exploiting the strengths of microsimulation in three dimensions, agents, space and time, in order to render them flexible platforms for policy evaluation. The effects of the current economic crisis are discussed and explored throughout the doctoral dissertation. Aiming to decrease the required budget for a LUTI model development, public on-line data are used to a large part of the analysis. Moreover, a graph-theoretic solution for associations generation in synthetic simulation is suggested. Different types of spatial econometric models are used for the development of real estate price models, which form fundamental component of every LUTI model. Urban quality indicators (i.e. accessibility, population segregation, economic viability, available open space, housing affordability, land-use and social mix, and building density) are effectively employed manifesting the benefits of trans-disciplinary collaboration in urban planning. In this research, a policy evaluation methodology based on distributions rather than single aggregate measures of quality indicators is proposed. The results indicate that spatial econometrics effectively remove the spatial autocorrelation and achieve higher accuracy than the traditional linear regression, in predicting the dwelling prices. The impact of transportation infrastructure locations on real estate purchase prices and rents differs, depending on the type of the transit system. Qualitative transit infrastructure has preserved the real estate prices at higher levels during the crisis. Synthetic populations and real, on-line, crowdsourced data can efficiently be used for the development of LUTI models. Finally, agent-based LUTI models provide an opportunity for the development of an improved, flexible policy evaluation platform.Δημήτριος Β. Ευθυμίο