3,436 research outputs found
Mrs. Cary L. Mitchell
No full textMrs. Cary L. Mitchell, new secretary of the Fort Worth Art Center School, looks at a photograph of author Somerset Maugham by Ida Kar. Fort Worth Star-Telegram Morning January 8, 1967.https://mavmatrix.uta.edu/specialcollections_startelegram1960s/3568/thumbnail.jp
Aspects of solute movement in the British uplands
Get PDFThe aim of this research is to determine the process by
which runoff draining parts of the UK uplands becomes
discoloured. Recent increases in colour are perceived as a
problem due to the frequency with which EC surface water
directives are breached, to the increased cost of meeting
standards, to an increase in consumer complaints, and due
to the possible deleterious health effects of consuming
coloured potable water.
The work was conducted over the last four years, largely in
the Upper Burn and Nidd valleys, north Yorkshire, and at
the University of Leeds. Existing knowledge on the chemical
nature and environmental genesis of coloured water is
reviewed, and related to the chemical nature of coloured
waters examined in this study. Analysis of water quality
archives and direct monitoring of selected catchments was
conducted enabling the spatial and temporal distribution of
coloured waters to be determined. A tentative process
theory was produced, and tested by controlled laboratory
investigations.
Coloured runoff is derived from Winter Hill soil, raw acid
oligo-fibrous peat, and is most intense from areas with
slopes < 5% and high drainage densities. The seasonal
pattern of colour is highly regular, and is a product of
rainfall and soil moisture deficit.
Colour is strongly associated with discharge, and demonstrates the operation of a catchment flushing mechanism. Runoff is discoloured in a three phase process; colour production, solubilisation and removal. Colour is a product of organic decomposition, dependent upon microbiological activity, moisture deficit, temperature and peat structure. Solubilisation of colour is dependent upon solution pH, temperature, the chemical structure of organic molecules and the availability of iron. The removal of decomposition products, as colour, is strongly dependent on the moisture status of peat, and its ability to rewet after drying. The implications of these findings for future colour levels and for catchment and catchwater management are discussed
Average seasonal changes in chlorophyll a in Icelandic waters
No full textThe standard algorithms used to derive sea surface chlorophyll a concentration from remotely sensed ocean colour data are based almost entirely on the measurements of surface water samples collected in open sea (case 1) waters which cover ~60% of the worlds oceans, where strong correlations between reflectance and chlorophyll concentration have been found. However, satellite chlorophyll data for waters outside the defined case 1 areas, but derived using standard calibrations, are frequently used without reference to local in situ measurements and despite well-known factors likely to lead to inaccuracy. In Icelandic waters, multiannual averages of 8-d composites of SeaWiFS chlorophyll concentration accounted for just 20% of the variance in a multiannual dataset of in situ chlorophyll a measurements. Nevertheless, applying penalized regression spline methodology to model the spatial and temporal patterns of in situ measurements, using satellite chlorophyll as one of the predictor variables, improved the correlation considerably. Day number, representing seasonal variation, accounted for substantial deviation between SeaWiFS and in situ estimates of surface chlorophyll. The final model, using bottom depth and bearing to the sampling location as well as the two variables mentioned above, explained 49% of the variance in the fitting dataset
Estimating specific inherent optical properties of tropical coastal waters using bio-optical model inversion and in situ measurements: case of the Berau estuary, East Kalimantan, Indonesia
No full textSpecific inherent optical properties (SIOP) of the Berau coastal waters were derived from in situ measurements and inversion of an ocean color model. Field measurements of water-leaving reflectance, total suspended matter (TSM), and chlorophyll a (Chl a) concentrations were carried out during the 2007 dry season. The highest values for SIOP were found in the turbid waters, decreasing in value when moving toward offshore waters. The specific backscattering coefficient of TSM varied by an order of magnitude and ranged from 0.003 m2 g-1, for clear open ocean waters, to 0.020 m2 g-1, for turbid waters. On the other hand, the specific absorption coefficient of Chl a was relatively constant over the whole study area and ranged from 0.022 m2 mg-1, for the turbid shallow estuary waters, to 0.027 m2 mg-1, for deeper shelf edge ocean waters. The spectral slope of colored dissolved organic matter light absorption was also derived with values ranging from 0.015 to 0.011 nm-1. These original derived values of SIOP in the Berau estuary form a corner stone for future estimation of TSM and Chl a concentration from remote sensing data in tropical equatorial water
Selective effects of errorful generation on recognition memory: the role of motivation and surprise
Get PDFThe current research examined the effects of errorful generation on memory, focusing particularly on the roles of motivation and surprise. In two experiments, participants were first presented with photographs of faces and were asked to associate four facts with each photograph. On Generate trials, the participants guessed two of the facts (Guess targets) before those correct facts, and another two correct facts (Study targets), were revealed. On the remaining Read trials, all four facts were presented without a guessing stage. In Experiment 1, participants also ranked their motivation to know the answers before they were revealed, or their surprise on learning the true answers. Guess targets were subsequently better recognised than the concurrently presented, non-guessed Study targets. Guess targets were also better recognised than Read targets, and recognition of Study and Read targets did not differ. Errorful generation also increased self-reported motivation, but not surprise. Experiment 2 showed that the results of Experiment 1 can outlive a 20-minute delay, and that they generalise to a more challenging recognition test. Together, the results suggest that errorful generation improves memory specifically for the guessed fact, and this may be linked to an increase in motivation to learn that fact
The physiology and biochemistry of the Laminaria Pallida/Carpoblepharis Minima and Ecklonia Maxima/Suhria Vittata associations from South-Western Cape waters, South Africa
No full textBibliography: leaves 129-140.The two laminarian brown algae Laminaria pallida Grev. ex. J. Ag. and Eoklonia maxima (Osb.) Papenf. are important both economically and as major components of the South-western Cape waters, South Africa. Growing attached to these brown algae are several different species of red algae two of which, Carpoblepharis minima Bart. and Suhria vittata (L.) J. Ag., were chosen and. the L. pallida/C. minima and. E. maxima/S. vittata associations were studied using physiological and biochemical methods. Carpoblepharis minima has only been observed on L. pallida, whereas S. vittata has been found attached to various substrates as well as to E. maxima
Geochemical and Isotopic Composition of Natural Waters in the Central Main Ethiopian Rift: emphasis on the study of source and genesis of fluoride
No full textIn the Main Ethiopian Rift (MER), the supply of drinking water principally relies on groundwater wells,
springs (including some hot springs), and rivers, and is characterized by a significant problem of
fluoride (F¯) contamination. New analyses reveal that the F− geochemical anomaly is sometimes
associated with hazardous content of other potentially toxic elements such as As, B, Mo, U, Al, Fe, and
Mn. The F¯ content exceeds the permissible limit for drinking prescribed by the World Health
Organization (WHO; 1.5 mg/L) in many important wells (up to 20 mg/L), with even more extreme F
concentration in hot springs and alkaline lakes (up to 97 mg/L and 384 mg/L respectively) and is
causing prevalent endemic fluorosis disease in the region.
87 % of the groundwater wells, 38 % of rivers and 100 % of hot springs and lakes show F¯ content
above 1.5 mg/L. The groundwater and surface water from the highlands, typically characterized by low
Total Dissolved Solids (TDS) and Ca2+ (Mg2+)-HCO3¯ hydrochemical facies, do not show high F¯
content. The subsequent interaction of these waters with the various rocks of the rift valley induces a
general increase of the TDS and a variation of the chemical signature towards Na+-HCO3¯
compositions, with a parallel enrichment of F¯. The interacting matrixes are mainly rhyolites consisting
of volcanic glass and only rare F-bearing accessory minerals (such as alkali amphibole).
Comparing the abundance and the composition of the glassy groundmass with other mineral phases, it
appears that the former stores most of the total F¯ budget. This glassy material is extremely reactive,
and its weathering products (i.e. fluvio/volcano-lacustrine sediments) further concentrate the fluoride.
The interaction of these “weathered/reworked” volcanic products with water and carbon dioxide at high
pH causes the release of fluoride into the interacting water. This mainly occurs by a process of baseexchange
softening with the neo-formed clay minerals (i.e. Ca-Mg uptake by the aquifer matrix, with
release of Na+ into the groundwater). This is plausibly the main enrichment mechanism that explains
the high F¯ content of the local groundwater, as evidenced by positive correlation between F¯, pH, and
Na+, and inverse correlation between F¯ and Ca2+ (Mg2+). Saturation indices (SI) were calculated (using
PHREEQC-2) for the different water groups, highlighting that the studied waters are undersaturated in
fluorite. In these conditions, fluoride can not precipitate as CaF2, and so F¯ mobilizes freely without
forming other complexes.
On the other hand, 35 % of the 23 investigated groundwater wells and 70 % of the 12 hot springs (and
deep geothermal wells) show Arsenic concentration above the recommended limit of 10μg/L (WHO
2006). The average concentration of Arsenic is 0.9μg/L in rivers, 39μg/L in hot springs, 236μg/L in
deep geothermal wells, 21.4μg/L in groundwater wells, 77μg/L in lakes, whereas maximum
concentrations reach up to 3μg/L, 156μg/L, 278μg/L, 157μg/L and 405 μg/L respectively. Arsenic in
groundwater wells shows positive correlations with Na+ (R2=0.63) and HCO3
− (R2=0.70) as well as with
other trace elements such as Mo (R2=0.79), U (R2=0.70), V (R2=0.68) whereas no correlations are
observed with Fe and Mn. PHREEQC speciation modelling indicates that Fe and Al oxides and
hydroxides are stable in the water systems, suggesting that Fe and Al mineral phases are potential
adsorbents and thus influence the mobility of As. The oxidizing, high pH condition combined with Na+-
HCO3¯ hydrochemical facies (competing effect of HCO3
− for adsorption sites) of the MER waters play
an important role in the mobilization of arsenic.
Chemical analyses of leachates from MER rhyolitic rocks and their weathered and reworked fluviolacustrine
sediments were performed in order to evaluate their contribution as a source of the mentioned
geochemical anomalies. The leachates were obtained from a one-year leaching experiment on powdered
rocks and sediments mixed with distilled water (10g:50ml). The sediment leachates contain as much as
7.6 mg/L of F¯, 220 μg/L of As, 181 μg/L of Mo, 64 μg/L of U and 254 μg/L of V suggesting that the
local sediments represent the main source and reservoir of toxic elements. Laboratory column
experiment was also conducted in volcanic ash sample using synthetic rain water flushing, and the result
showed that significant amount of F¯ were leached out over the duration of the experiments.
This showed that these elements were originally present in the glassy portion of the MER rhyolitic
rocks, were progressively concentrated in weathered and redeposited products. It further confirms that
the pyroclastic materials are the major source and reservoir of many of the chemical elements (e.g. F¯,
As). Therefore, together with the renowned F¯ problem, the possible presence of geochemical
anomalies in As, B, Mo, V, U, Al, Fe, and Mn have to be taken into consideration in water quality issues
and future works has to investigate their possible health impact on the population of MER and other
sectors of the east African rift.
The stable δ18O, δD and radiogenic (87Sr/86Sr) isotopic composition of waters and representative
volcanic rocks (Ignimbrite and basalt) were carried out during this study. Different ranges of isotopic
values were recorded for different water groups: 10 hot spring samples show δ18O value with in the range of (-3.36‰ – 3.69‰) and δD (-0.95‰ – 24.23‰) (VSMOW), 12 groundwater wells δ18O (-
3.99‰ – 5.14‰) and δD (-19.69‰ – 32.27‰) in contrast to the 5 Lakes δ18O (3.98‰ – 7.92‰) and δD
(26.19‰ – 45.71‰). The 2 deep geothermal wells and 1 of the 2 river samples are depleted in stable
isotopic values. 87Sr/86Sr values range from 0.7045 to 0.7076 in the hot springs, and the two deep
geothermal wells have 0.7043 and 0.7054 values. These signatures are typical of water interacted with
mantle derived materials (with a minor crustal contamination), similar to the rocks widely covering the
study area. The Sr isotope values of the basalt and ignimbrite samples are 0.7063 and 0.7071
respectively. Generally, the result shows that there exists a complex surface water and groundwater
interactions that is reflected on a diversity of the stable and Sr isotopic signature in waters.
The preliminary results of the study has showed that there is a need for future extended works on the
geochemistry of solid samples (rocks, sediments and soils) as well as in waters that investigate all the
spectrum of chemical elements that are potentially detrimental to human health and environment.
Furthermore, from water resource point of view, the following works must focus on a comprehensive
study of various isotopes and geochemical data to constrain groundwater age dating, water-rock
interaction and flow path and thus help to model and systematize the hydrologic cycles in the basin
Estimation of phytoplankton concentration from downwelling irradiance measurements in water
No full textThe downwelling irradiance spectrum is so far not used directly for the determination of water constituents, mainly due to the large and unpredictable fluctuations of the underwater light field induced by the water surface. The potential of a new analytical model, which can cope with such environmental influences, was analyzed for the estimation of phytoplankton concentration using data from two German lakes. It turned out that the model is able to determine in these lakes phytoplankton concentration above a threshold between 0.4 and 0.9 µg/l, depending on the phytoplankton class, and total pigment concentration (sum of chlorophyll-a and phaeophytin-a) with an uncertainty of 0.7 µg/l. This new in situ spectroscopy method is particularily of interest for shallow waters, where it is difficult to apply the usual reflectance-based algorithms due to bottom influences
Building the case for culturally specific prenatal through grade 3 strategies in Oregon
No full textprepared by Callie H. Lambarth, Amanda Cross-Hemmer, Lorelei Mitchell, Beth L. Green and Kate Normand.Title from PDF cover (viewed on December 30, 2019).Covers OCLC #1134399567 and OCLC #1134399474.This archived document is maintained by the State Library of Oregon as part of the Oregon Documents Depository Program. It is for informational purposes and may not be suitable for legal purposes.Includes bibliographical references.Mode of access: Internet from the Oregon Government Publications Collection.Text in English
Taxonomy of the fouling cheilostome bryozoans, Schizoporella unicornis, (Johnston) and Schizoporella errata (Waters)
No full textFigure 1. (A–D) Images of Wood's Pliocene specimen from the Coralline Crag, Suffolk (NHM B1675) described in Busk (1859). (A) Group of autozooids at growing edge of colony within small bivalve shell. (B) Autozooids exhibiting deep V-shaped sinus. (C) Frontal shield with paired avicularia and deep V-shaped sinus. (D) Detail of primary orifice and sinus. (E, F) Lectotype of Schizoporella unicornis [NHM 1847.16.174 (a)] bleached portion. (E) Group of autozooids at the distal edge of colony with adventitious avicularia, paired, single or absent. (F) Ovicellate autozooids showing radially aligned scalloped grooves. Scale bars: 500 µm (A); 250 µm (B); 100 µm (C, E); 50 µm (D,F).Published as part of Tompsett, Scott, Porter, Joanne S. & Taylor, Paul D., 2009, Taxonomy of the fouling cheilostome bryozoans Schizoporella unicornis (Johnston) and Schizoporella errata (Waters), pp. 2227-2243 in Journal of Natural History 43 (35-36) on page 2231, DOI: 10.1080/00222930903090140, http://zenodo.org/record/521715
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