Acceptance of open source geospatial software: Assessing QGIS in South Africa with the UTAUT2 model

Geospatial information and technologies are widely used in South Africa, initially mostly with proprietary software but today, mature, open source alternatives such as QGIS are available. We wanted to find out if and why South African users accepted QGIS, globally the most widely used free and open source GIS. We adapted the extended unified theory of acceptance and use of technology model to test several hypotheses regarding the acceptance and use of QGIS in South Africa. 205 registered members of the Geo‐Information Society of South Africa completed a structured questionnaire. Results show that habit has the most significant influence on behavioural intention to use QGIS, followed by facilitating conditions, price value and social influence. Performance expectancy, effort expectancy, hedonic motivation and access to source code played no significant role. The findings show that adoption of QGIS in South Africa is not primarily influenced by benefits attributed to open source software, such as cost benefits, customizability, improved reliability, quality and security. The results are useful for developers of any GIS product and for choosing a GIS product for an organization, because they provide insight into the behavioural intentions of users.     

2015–2020 Geological Survey Program of China Geological Survey Bureau

正On 1–5 September 2014,the China Geological Survey Bureau held a 2015–2020 Geology and Mineral Resources Investigation and Assessment Special Planning and Deployment Meeting to plan the next six years in order to invest nearly ten billion US dollars to implement 9 programs and 50 projects with the aim of developing geological survey work,and to play a leading role in ensuring sustained and stable development.1 The Land Energy and Mines Geological Survey Program     

Adaptation, Spatial Heterogeneity, and the Vulnerability of Agricultural Systems to Climate Change and CO2 Fertilization: An Integrated Assessment Approach

In this paper we develop economic measures of vulnerability to climate change with and without adaptation in agricultural production systems. We implement these measures using coupled, site-specific ecosystem and economic simulation models. This modeling approach has two key features needed to study the response of agricultural production systems to climate change: it represents adaptation as an endogenous, non-marginal economic response to climate change; and it provides the capability to represent the spatial variability in bio-physical and economic conditions that interact with adaptive responses. We apply this approach to the dryland grain production systems of the Northern Plains region of the United States. The results support the hypothesis that the most adverse impacts on net returns distributions tend to occur in the areas with the poorest resource endowments and when mitigating effects of CO₂ fertilization and adaptation are absent. We find that relative and absolute measures of vulnerability depend on complex interactions between climate change, CO₂ level, adaptation, and economic conditions such as relativeoutput prices. The relationship between relative vulnerability and resource endowments varies with assumptions about climate change, adaptation, and economic conditions. Vulnerability measured with respect to an absolute threshold is inversely related to resource endowments in all cases investigated.     

Fe isotopic fractionation during mineral dissolution with and without bacteria

Fe released into solution is isotopically lighter (enriched in the lighter isotope) than hornblende starting material when dissolution occurs in the presence of the siderophore desferrioxamine mesylate (DFAM). In contrast, Fe released from goethite dissolving in the presence of DFAM is isotopically unchanged. Furthermore, Δ⁵⁶Fe_{solution-hornblende} for Fe released to solution in the presence of ligands varies with the affinity of the ligand for Fe. The extent of isotopic fractionation of Fe released from hornblende also increases when experiments are agitated continuously. The Fe isotope fractionation observed during hornblende dissolution with organic ligands is attributed predominantly to retention of ⁵⁶Fe in an altered surface layer, while the lack of isotopic fractionation during goethite dissolution in DFAM is consistent with the lack of an altered layer. When a siderophore-producing soil bacterium is added to the system (without added organic ligands), Fe released to solution from both hornblende and goethite differs isotopically from Fe in the bulk mineral: Δ⁵⁶Fe_{solution-starting material} = −0.56 ± 0.19 (hornblende) and −1.44 ± 0.16 (goethite). Increased isotopic fractionation is attributed in this case to the fact that as bacterial respiration depletes the system in oxygen and aqueous Fe is reduced, equilibration between aqueous ferrous and ferric iron creates a pool of isotopically heavy ferric iron that is assimilated by bacterial cells. Adsorption of isotopically heavy ferrous iron (Fe(II) enriched in the heavier isotope) or precipitation of isotopically heavy Fe minerals may also contribute to observed fractionations.To test whether these Fe isotope signatures are recorded in natural systems, we also investigated extractions of samples of soils from which the bacteria were isolated. These extractions show variability in the isotopic signatures of exchangeable Fe and Fe oxyhydroxide fractions from one soil sample to another, but exchangeable Fe is observed to be lighter than Fe in soil Fe oxyhydroxides and hornblende. This observation is consistent with isotopically light Fe-organic complexes in soil pore water derived from the Fe-silicate starting materials in the presence of growing microorganisms, as documented in experiments reported here. The contributions from phenomena including organic ligand-promoted nonstoichiometric dissolution of Fe silicates, uptake of ferric iron by organisms, adsorption of isotopically heavy ferrous iron, and precipitation of iron minerals should create complex isotopic signatures in soils. Better understanding of these processes and the timescales over which they contribute to fractionation is needed.     

Correlations among hydrocarbon microseepage, soil chemistry, and uptake of micronutrients by plants, Bell Creek oil field, Montana

Chelate-extractable iron and manganese concentrations in soils over and around the Bell Creek oil field suggest that compared to low average background values, there are moderate amounts of these elements directly over the production area and higher concentrations distributed in an aureole pattern around the periphery of the field. Adsorbed and organically bound iron and manganese appear to be readily taken up by plants resulting in anomalously high levels of these elements in leaves and needles over the oil field and suggesting correlation with corresponding low concentrations in soils. Iron and manganese appear to have bypassed the soil formation process where, under normal oxidizing conditions, they would have ultimately precipitated as insoluble oxides and hydroxides.     

Evaluating shallow flow-system response to climate change through analysis of spring deposits in southwestern Wisconsin,USA

Tufa-depositing springs in the southern Driftless Area of Wisconsin, USA, are used to inform the response of shallow and local groundwater flow systems to changes in climate over the last 3,000 years. The springs emanate from a shallow, unconfined, sedimentary bedrock aquifer and at stratigraphic positions similar to a shallow, perched aquifer that was identified in the eastern Driftless Area. The perched aquifer was shown to be stable under current climate conditions and over decadal time scales. This study provides further evidence of the significance of the stratigraphic interval in controlling shallow groundwater flow patterns in the region and in the stability of shallow and local groundwater flow systems over thousands of years. The tufa carbonates in three cores collected from the mounds adjacent to the springs show variations in stable isotope (δ¹³C, δ¹⁸O) and elemental (Mg/Ca) values that agree with well-established paleoclimate records for the region, suggesting that the springs were active and depositing tufa in the past, during climate conditions that were similar to the present and during conditions that were drier than the present.     

Diel variation in immigration of fishes and decapod crustaceans to artificial seagrass habitat

Fish and decapod entry into small (1.5 m²) artificial seagrass habitats positioned on an open sand area in a New Jersey estuary was examined to determine if immigration varied between day and night. To encounter the structured habitats, colonizers had to cross an expanse of bare sand, with its presumably higher predation risk. Contrasts in abundance in the artificial seagrass plots between dawn and dusk indicated higher nighttime immigration for four species, including the fishesFundulus heteroclitus andMyoxocephalus aenaeus, and the caridean shrimpsPalaemonetes vulgaris andHippolyte pleuracanthus. Size-frequency distributions of colonizers varied between day and night for two fish species,Menidia menidia andSyngnathus fuscus, with a greater proportion of smaller individuals immigrating to the artificial seagrass at night.Callinectes sapidus also displayed a diel contrast in size distribution but, for this species, proportionately more small individuals colonized the plots during the day. We suggest that diel variability in predation risk and/or diel patterns in motor activity may be responsible for these patterns in immigration.     

Compositional and Isotopic Analytical Methods in Archaeological Micromorphology

Resin‐impregnated sediment blocks are a by‐product of micromorphological sample processing. These blocks can be further studied using a variety of destructive, nondestructive, and minimally destructive geochemical techniques. X‐ray fluorescence microanalyses conducted on sediment blocks yield semiquantitative major and trace elemental abundances that can be used to generate compositional maps, and to illustrate compositional change within or between archaeological strata and features. Sediment blocks can also be drilled to obtain small sediment samples for stable oxygen and carbon isotopic analyses. Both elemental and isotopic analyses can be conducted in conjunction with micromorphological analyses to yield a holistic picture of archaeological sediment composition, source, and depositional processes. The integration of micromorphological, compositional, and isotopic analyses is used here to aid in the differentiation of calcareous ash and lime plasters from the Neolithic site of Asıklı Höyük, Turkey.     

A new isogon-cleavage classification and its application to natural and model fold studies

Traditional methods of studying natural folds are reviewed. A new method of describing cleavage attitude in folds is presented; the β plot. The combined graph of dip isogon angle ϕ (Hudleston 1973) and cleavage angle β is proposed as a linked classification of fold and cleavage geometry. Plots of β and βϕ are given for three natural fold examples. The classification is extended to the geometry and strain attitude (βϕ₅) of two finite-element models and the classical folding models. Results are compared and some tentative conclusions drawn on the relationship of cleavage, the XY plane of strain and dip isogons.