title: Effect of boron-doped goethite on soil acidity, different forms of manganese in red soil and the growth of rape (brassica napus l.) seedlings

authors: Cui, Jingzhen

subjects: boron-doped goethite

abstract: Rape (Brassica napus L.) seedling pot experiments were performed with a red soil treated with goethite which had boron (B) either adsorbed (ad-B-goethite) or occluded (oc-B-goethite). Soil acidity, different forms of manganese in the soils and different elements content of the rape seedlings were determined. It was found that the addition of boron-containing goethite to the soils resulted in increased rape growth, elevated soil pH and decreased exchangeable acidity. Compared with the control, boron-containing goethite elevated the content of exchangeable manganese (Mn) (EXC-Mn), organic matter bound Mn (OM-Mn), reducible oxide Mn (RO-Mn) and residual Mn (RES-Mn) which were difficult to use for plant. Low labile organic matter was significantly correlated with easily reducible oxide Mn (ERO-Mn) (P < 0.01) and RO-Mn (P < 0.05). Middle organic matter and soil pH was significantly (P < 0.05) correlated with RES-Mn. Stepwise regression was used to select the combination of variables that best estimates shoot and root dry weight of rape seedling. Among them, soil pH, EXC-Mn, OM-Mn, RO-Mn and RES-Mn significantly influenced the dry weight of rape seedlings. The addition of boron-containing goethite improved the uptake of iron (Fe), calcium (Ca), magnesium (Mg), and copper (Cu) element and decreased the uptake of Mn and zinc (Zn) element in rape seedling. The results suggested that boron-containing goethite could provide a better soil acidity environment for plant growth; it was also an important agent increasing a part of manganese difficult to use for plant and reducing the activity of soil manganese, which was beneficial to altering rape seedling growth.

text: Effect of boron-doped goethite on soil acidity, different forms of manganese in red soil and the growth of rape (brassica napus l.) seedlings Rape (Brassica napus L.) seedling pot experiments were performed with a red soil treated with goethite which had boron (B) either adsorbed (ad-B-goethite) or occluded (oc-B-goethite). Soil acidity, different forms of manganese in the soils and different elements content of the rape seedlings were determined. It was found that the addition of boron-containing goethite to the soils resulted in increased rape growth, elevated soil pH and decreased exchangeable acidity. Compared with the control, boron-containing goethite elevated the content of exchangeable manganese (Mn) (EXC-Mn), organic matter bound Mn (OM-Mn), reducible oxide Mn (RO-Mn) and residual Mn (RES-Mn) which were difficult to use for plant. Low labile organic matter was significantly correlated with easily reducible oxide Mn (ERO-Mn) (P < 0.01) and RO-Mn (P < 0.05). Middle organic matter and soil pH was significantly (P < 0.05) correlated with RES-Mn. Stepwise regression was used to select the combination of variables that best estimates shoot and root dry weight of rape seedling. Among them, soil pH, EXC-Mn, OM-Mn, RO-Mn and RES-Mn significantly influenced the dry weight of rape seedlings. The addition of boron-containing goethite improved the uptake of iron (Fe), calcium (Ca), magnesium (Mg), and copper (Cu) element and decreased the uptake of Mn and zinc (Zn) element in rape seedling. The results suggested that boron-containing goethite could provide a better soil acidity environment for plant growth; it was also an important agent increasing a part of manganese difficult to use for plant and reducing the activity of soil manganese, which was beneficial to altering rape seedling growth.

year: 2012

title: Summer meltwater and spring sea ice primary production, light climate and nutrients in an Arctic estuary, Kangedussuaq, west Greenland

authors: Lund-Hansen, Lars Chresten

subjects: Science & Technology

abstract: The estuary is dominated by sea ice and snow cover from winter to spring, and a highly turbid meltwater plume during summer. The aims were to quantify the variability in optical conditions, inorganic nutrients, and primary production between these two extremes, and identify the drivers of variability. Data were obtained during a summer cruise along a transect in the estuary in August 2007, and a spring campaign on the ice in March 2011. The study comprises conductivity, temperature, and depth (CTD), K𝒹(PAR), K𝒹(λ), PAR transmittance, photic depth, chl-a, nutrients (NO₃, NO₂, NH₃, PO₄, and SiO₂), primary production, and sediment concentrations. PAR transmittance varied between 5% below snow and ice and 85% in clear water with 44% in turbid meltwater. Primary production rates were similar below the ice in March (76.8 mg C m⁻² d⁻¹) and in the highly turbid meltwater in August (94.8 mg C m⁻² d⁻¹), but higher (246.6 mg C m⁻² d⁻¹) at the mouth of the fjord. Meltwater inflow was the main driver of variability during summer and the snow and sea ice during spring. Under-ice primary production will increase three-fold with less snow on the sea ice, and the higher meltwater turbidity with increased melting of glacial ice and runoff will only reduce primary production slightly.

text: Summer meltwater and spring sea ice primary production, light climate and nutrients in an Arctic estuary, Kangedussuaq, west Greenland The estuary is dominated by sea ice and snow cover from winter to spring, and a highly turbid meltwater plume during summer. The aims were to quantify the variability in optical conditions, inorganic nutrients, and primary production between these two extremes, and identify the drivers of variability. Data were obtained during a summer cruise along a transect in the estuary in August 2007, and a spring campaign on the ice in March 2011. The study comprises conductivity, temperature, and depth (CTD), K𝒹(PAR), K𝒹(λ), PAR transmittance, photic depth, chl-a, nutrients (NO₃, NO₂, NH₃, PO₄, and SiO₂), primary production, and sediment concentrations. PAR transmittance varied between 5% below snow and ice and 85% in clear water with 44% in turbid meltwater. Primary production rates were similar below the ice in March (76.8 mg C m⁻² d⁻¹) and in the highly turbid meltwater in August (94.8 mg C m⁻² d⁻¹), but higher (246.6 mg C m⁻² d⁻¹) at the mouth of the fjord. Meltwater inflow was the main driver of variability during summer and the snow and sea ice during spring. Under-ice primary production will increase three-fold with less snow on the sea ice, and the higher meltwater turbidity with increased melting of glacial ice and runoff will only reduce primary production slightly.

year: 2018

title: The general cognitive ability of Maori and European subjects: a comparative study of Queensland test performances and psychometric properties

authors: St George, Ross

abstract: Research was undertaken into the performances of New Zealand Maori and European children on the Queensland Test of Cognitive Abilities. In addition to studying the comparative performances of the two ethnic groups at six age levels, major psychometric properties of the instrument were investigated. Such data have an important bearing upon the issue of psychological equivalence across ethnic or culture group samples.
Seven hundred children (303 Maori and 397 European) aged between eight and a half and fourteen and a half years were tested with the Queensland Test. A small statistically significant ethnic group difference was found favouring the European children. Subsequent analyses indicated that the small difference was of little practical significance. Queensland Test subtest data were also analysed, This indicated that subtest performances were likely to be influenced by subject variables in a manner not necessarily evident in the overall test results. Gender differences in performance on the Pattern Matching Subtest were found and are consistent with other data. 
Queensland Test reliability, validity and item characteristics were researched for the two ethnic groups. 
To obtain test-retest reliability estimates and data on criterion related validity longitudinal studies were undertaken with four ethnically mixed class groups Standard 3 to Form 2). 
The Queensland Test was found to be equally reliable with both ethnic groups although the levels of reliability obtained were not considered entirely satisfactory. 
Validity data indicated that the same general intelligence construct could be employed in the interpretation of Queensland Test results with both European and Maori subjects. Content validity issues were considered and it was argued that in terms of both test content and measurement procedures the Queensland Test should provide an equally valid measure of general intelligence with both groups. 
The criterion related validity coefficients were of approximately the same order for each ethnic group although doubts were expressed about the adequacy of the criteria. Construct validity was investigated by considering the relationship of test performance to age and through factor analytic evidence. The analyses supported the view that the Queensland Test was primarily a measure of the same underlying construct within each ethnic group. In terms of prevailing psychological theories on human intelligence this construct was interpreted as being of a general intelligence nature.
Comparative data on item characteristics did not indicate any marked ethnic group differences. More apparent was the need to restructure particular subtests where items failed to discriminate adequately within both ethnic groups. It was concluded that the weight of evidence was in favour of the psychological equivalence of this ability measure with Maori and European children. 
Data for combined ethnic group samples have been reported, Pooled data were employed in some factor analyses and these supported a general intelligence interpretation of Queensland Test results. Preliminary norms were also derived from combined ethnic group data. 
Findings are discussed in relation to the concept of intelligence and its cross-cultural measurement, other Queensland Test research and recent cross-cultural studies on cognitive abilities in New Zealand.

text: The general cognitive ability of Maori and European subjects: a comparative study of Queensland test performances and psychometric properties Research was undertaken into the performances of New Zealand Maori and European children on the Queensland Test of Cognitive Abilities. In addition to studying the comparative performances of the two ethnic groups at six age levels, major psychometric properties of the instrument were investigated. Such data have an important bearing upon the issue of psychological equivalence across ethnic or culture group samples.
Seven hundred children (303 Maori and 397 European) aged between eight and a half and fourteen and a half years were tested with the Queensland Test. A small statistically significant ethnic group difference was found favouring the European children. Subsequent analyses indicated that the small difference was of little practical significance. Queensland Test subtest data were also analysed, This indicated that subtest performances were likely to be influenced by subject variables in a manner not necessarily evident in the overall test results. Gender differences in performance on the Pattern Matching Subtest were found and are consistent with other data. 
Queensland Test reliability, validity and item characteristics were researched for the two ethnic groups. 
To obtain test-retest reliability estimates and data on criterion related validity longitudinal studies were undertaken with four ethnically mixed class groups Standard 3 to Form 2). 
The Queensland Test was found to be equally reliable with both ethnic groups although the levels of reliability obtained were not considered entirely satisfactory. 
Validity data indicated that the same general intelligence construct could be employed in the interpretation of Queensland Test results with both European and Maori subjects. Content validity issues were considered and it was argued that in terms of both test content and measurement procedures the Queensland Test should provide an equally valid measure of general intelligence with both groups. 
The criterion related validity coefficients were of approximately the same order for each ethnic group although doubts were expressed about the adequacy of the criteria. Construct validity was investigated by considering the relationship of test performance to age and through factor analytic evidence. The analyses supported the view that the Queensland Test was primarily a measure of the same underlying construct within each ethnic group. In terms of prevailing psychological theories on human intelligence this construct was interpreted as being of a general intelligence nature.
Comparative data on item characteristics did not indicate any marked ethnic group differences. More apparent was the need to restructure particular subtests where items failed to discriminate adequately within both ethnic groups. It was concluded that the weight of evidence was in favour of the psychological equivalence of this ability measure with Maori and European children. 
Data for combined ethnic group samples have been reported, Pooled data were employed in some factor analyses and these supported a general intelligence interpretation of Queensland Test results. Preliminary norms were also derived from combined ethnic group data. 
Findings are discussed in relation to the concept of intelligence and its cross-cultural measurement, other Queensland Test research and recent cross-cultural studies on cognitive abilities in New Zealand.

year: 1977