bluuebunny/crossref_metadata_2025 huggingface dataset:
HALOMORPHISM OF SOME CLAY SOILS IN MANITOBA
Authors: Ehrlich W. A. , Smith R. E.
Published: March 2010

The analysis of the principal horizons of 11 halomorphic profiles was undertaken in an attempt to ascertain, chiefly, the kind and quantity of soluble salts and exchangeable cations assumed to be the main causative agents in the formation of solonetzic soils in Manitoba. The results showed that water-soluble sodium was equal to or greater in quantity than water-soluble calcium or water-soluble magnesium; that exchangeable calcium followed closely by exchangeable magnesium dominated the exchange complexes; and that exchangeable sodium in excess of 15 per cent of the exchangeable cations was found only in some horizons of the Solonchak, Solonetz and Solodized-Solonetz soils in the Chesterfield Association.
RATE OF CHANGE OF pH IN SOME ACID SOILS DUE TO LIMING
Authors: Nielsen K. F.
Published: March 2010

Lime at the rate of 0, 3000, 6000, 12,000 and 24,000 pp2m was applied to four acid soils and allowed to incubate for a period of 140 days. The rate and extent of change in pH was followed.In all four soils the rate of reaction was very rapid and most of the increase in pH was obtained within 3 days after application. At all rates of liming in the four soils there was a general decrease in pH following the peak obtained within the first 30 days.It was also found that the rate of change in pH of a soil that had been limed was greatly influenced by the moisture content. The change in pH was much more rapid and extensive at 25 per cent moisture than at 10 per cent.
SEASONAL pH FLUCTUATIONS IN A GREY WOODED SOIL
Authors: Bowser W. E. , Leat J. N.
Published: March 2010

Seasonal fluctuations in pH values were determined on soil samples from a modal Grey Wooded soil (Cooking Lake series). Samples were collected from the A0, A2, and B1 horizons at regular intervals from May to November. During this period the pH of each horizon varied from neutral to strongly acid. These fluctuations appeared to be related to the soil moisture and possibly to the soil temperature regime.
THE EFFECT OF SOIL AGGREGATE SIZE ON AVAILABILITY OF OXYGEN AND ON GROWTH OF TOMATOES
Authors: Doyle J.J. , MacLean A. A.
Published: March 2010

Diffusion of oxygen was measured by the platinum micro-electrode method on seven sizes of artificially prepared soil aggregates. Diffusion of oxygen was directly proportional to aggregate size.Growth of tomato plants increased with aggregate size and with diffusion rate of oxygen.For a temperature of 68° F., and with the surface of the soil at a moisture tension of 20 cm., critical diffusion rates of oxygen are suggested for the 2-, 4- and 6-inch depths of 12 × 10−7, 8 × 10−7 and 6 × 10−7 grams/cm2/min., respectively.A thorough study of the performance of the platinum micro-electrode method under field conditions is recommended, with a view to adapting it for the direct assessment in the field of soil physical condition and for the establishment of critical levels of oxygen for crops.
MINERALOGICAL ANALYSIS OF THE SOILS OF THE MARITIME PROVINCES
Authors: Brydon J. E.
Published: March 2010

The mineralogy of the clay and coarse silt fractions of 31 Maritime soils with a few exceptions showed close similarities. The predominant clay mineral was illite and it was associated with chlorite, vermiculite and kaolinite. Significant amounts of montmorillonite occurred in only one soil, the Truro. Vermiculite appeared in all the surface soil clays, and mixed-layer assemblages of various 2:1 layer silicates, including chloritic components, were present in many of the clays.The silt fractions of the Nova Scotia and New Brunswick soils contained substantial amounts of albite-type plagioclase feldspar in addition to quartz, chlorite and mica. The Prince Edward Island soils, except the Queens, differed in that they contained small amounts of a variety of feldspars.
A MINERALOGICAL AND CHEMICAL STUDY OF THE DIKELAND SOILS OF NOVA SCOTIA
Authors: Brydon J. E. , Heystek H.
Published: March 2010

Six profiles taken from the dikeland areas of Nova Scotia were examined chemically and mineralogically. The mineralogy of the various layers was similar within and between profiles, except that the reddish layers contained goethite while the grey layers did not. The latter were very strongly acidic and had an unusually high organic matter content due to burial of undecomposed vegetation by tidal sediments. While they contained no goethite, they had a significant amount of "free iron". It is proposed that where sufficient organic matter was available the grey layers were produced by anaerobic bacterial reduction of the reddish iron oxides.Quartz was the predominant non-clay mineral associated with mica, feldspar and chlorite. The clay fraction consisted of illite with characteristics of muscovite, chlorite similar to "swelling" chlorite, kaolinite and montmorillonite.
THE INFLUENCE OF BURNING ON THE SOIL IN THE TIMBER RANGE AREA OF LAC LE JEUNE, BRITISH COLUMBIA: II. CHEMICAL PROPERTIES
Authors: Beaton J. D.
Published: March 2010

The effects of fire on certain soil chemical properties were investigated on soil samples taken from the surface organic layer (O horizon) and the immediately underlying leached mineral layer (A2 horizon) from seven different burns and from corresponding unburned areas present within each burned-over area. Burning resulted in an increase in the pH, total phosphorus content, and CO2-soluble calcium content of the O horizon of most of the soils studied. As a consequence of fire, the O horizon was reduced in organic matter, total nitrogen and carbonic acid-soluble phosphorous and magnesium. Most of the effects of fire upon soil chemical properties were apparently restricted to the O horizon since no significant trends were evident in the underlying A2 horizon.
INFLUENCE OF BULK DENSITY AND FIELD STRUCTURE OF SOIL ON THE CALIBRATION CURVES OF GYPSUM MOISTURE BLOCKS
Authors: Bocrget S. J.
Published: March 2010

Gypsum moisture blocks were calibrated in the laboratory in undisrupted soil cores, in soil cores which had been repacked to field density, and in unpacked soil baskets. Three soil types were used. It was found that the calibration curves obtained in the repacked soil cores and in the soil baskets were different from those obtained in the undisrupted soil cores. This indicates that the disruption of both structure and bulk density influenced the calibration of gypsum blocks. The effects were greater on the fine textured than on the coarse textured soils. The influence of bulk density was not important on a sandy loam soil. The variations in soil moisture obtained ranged from 1 to 6 per cent within the available water range.
THE AVAILABILITY TO ALFALFA OF PHOSPHORUS FROM TWELVE DIFFERENT CARRIERS
Authors: Beaton J. D. , Nielsen K. F.
Published: March 2010

Availabilities of the phosphorus in twelve different phosphate sources to alfalfa were determined in a growth chamber. Two crops of alfalfa were grown on two soils of high base status, Machete stony sandy loam and Westwold loam. Fertilizer materials containing monocalcium phosphate or materials such as calcium metaphosphate which are converted to monocalcium phosphate brought about the greatest increases in yield. However, yield increases also resulted from treatments with the ammonium phosphates and orthophosphoric acid. Ammonium phosphate fertilizers were the most effective in increasing the percentage of phosphorus present in the alfalfa tissue. Ammonium phosphate and monocalcium phosphate materials were equally effective in increasing total phosphorus uptake by alfalfa. The amount of CO2 soluble phosphorus extracted from the Westwold loam, following treatment with the various phosphate sources, was correlated with the yield of the first crop of alfalfa. The average per cent P in the alfalfa tissue was found to be correlated with the CO2 soluble P. Both the NaHCO3 and CO2 extractable soil phosphorus levels of the Westwold loam, after it had been treated with the different phosphate materials, were found to be highly correlated with the phosphorus uptake by the second crop of alfalfa and with the total phosphorus uptake.
STUDIES WITH WASTE SULPHITE LIQUOR: I. EFFECTS OF WASTE SULPHITE LIQUOR ON CROP YIELDS AND ON SOIL PROPERTIES
Authors: MacLean A. A. , Doyle J. J.
Published: March 2010

A greenhouse investigation was conducted to assess the effects of waste sulphite liquor solids (W.S.L.S.) on crop yields and on some chemical and physical properties of an Interval silt loam soil. The response of oats and Italian ryegrass to nitrogen applied as ammonium sulphate served as a standard for evaluating the 3 per cent nitrogen contained in the ammonium-base W.S.L.S.Significant increases in yields of oats and ryegrass resulted from ammonium sulphate-nitrogen at rates of 60 and 120 lb. per acre respectively. W.S.L.S. at 2 tons per acre, supplying 120 lb. per acre of nitrogen, gave increases of a similar magnitude. Higher rates of W.S.L.S. gave additional increases in yields. The nitrogen content of the two crops was increased by applying W.S.L.-nitrogen at 480 lb. per acre. Ammonium-sulphate nitrogen at 60 lb. per acre and W.S.L.-nitrogen at 120 lb. per acre increased the total nitrogen uptake by oats and ryegrass.W.S.L.S. increased the organic matter content, cation exchange capacity and exchangeable hydrogen of this alluvial soil. Ammonium sulphate-nitrogen at 120 lb. per acre and W.S.L.S. at 2 tons per acre or more depressed soil pH.Additions of W.S.L.S. increased the percentage of water stable aggregates but did not affect the moisture equivalent.
EXCHANGEABLE AND WATER-SOLUBLE POTASSIUM IN SOILS AND DEGREE OF SATURATION IN RELATION TO TOMATO YIELDS
Authors: Halstead R. L. , Heeney H. B.
Published: March 2010

In 33 field trials on soils varying in texture from sandy loam to clay loam in Prince Edward County, Ontario, exchangeable potassium, per cent potassium saturation, and water-soluble potassium were significantly correlated with yield response of tomatoes to potassium fertilizer on the sandy loam soils, but there was no correlation within the loam and clay loam groups. The mean c1 value in the modified Mitscherlich equation relating exchangeable potassium to yield response within the sandy loam group was 0.00555 and the coefficient of variation was 19.8 per cent. The corresponding coefficients for c1 values based on per cent potassium saturation and water-soluble potassium were of greater magnitude. The amounts of potassium soluble in boiling 1 N HNO3 were not related to yield response.Exchangeable potassium and the non-exchangeable form soluble in boiling 1 N HNO3 increased, whereas water-soluble potassium decreased with increasing clay content of the samples. Water-soluble potassium was significantly correlated with per cent potassium saturation within the sandy loam and loam groups.
EFFECT OF CROPPING SYSTEMS AND FERTILIZERS ON MEAN WEIGHT-DIAMETER OF AGGREGATES OF BRETON PLOT SOILS
Authors: Toogood J. A. , Lynch D. L.
Published: March 2010

Aggregate analyses of Breton plot soils using a wet sieving technique revealed marked differences resulting from cropping practices but few, if any, due to fertilizers. The mean weight-diameter of soils from plots in a 5-year rotation of grains and legumes was almost double the diameter of soils from plots in a wheat-fallow sequence. With respect to fertilizers, however, mean weight-diameter of soils from high yielding plots in either cropping system were in general similar to those on low-yielding plots of the system in question. Incidentally polysaccharide content of the soil showed a definite relationship to mean weight-diameter.
A STUDY OF SOME PROFILES FROM MAJOR SOIL ZONES IN SASKATCHEWAN AND ALBERTA
Authors: Rice H. M. , Forman S. A. , Patry L. M.
Published: March 2010

Mineralogical studies of three profiles from Saskatchewan and two from Alberta showed that the predominant clay minerals were montmorillonite and illite. Some kaolinite was found in the coarse and medium fractions of the clays. The three Saskatchewan profiles were almost identical from a mineralogical point of view. The two Alberta soils differed from these in a few minor aspects such as having slightly more quartz and considerably less feldspars in the silt and clay fractions. Degradation of the montmorillonite in the upper horizons of the Saskatchewan profiles was demonstrated.
A MINERALOGICAL STUDY OF SOME CORE SAMPLES FROM THE BEARPAW FORMATION
Authors: Forman S. A. , Rice H. M.
Published: March 2010

A mineralogical study was made of some drill cores of Bearpaw shales from the site of the proposed power and irrigation dam on the South Saskatchewan River. Mechanically, the samples fell into three distinct groups, viz., Group 1: low sand, high silt, and high clay; Group 2: high sand, moderate silt, and high clay; Group 3: high sand, low silt, and very high clay. A sample which showed lesser shear strength when compared with the others fell into Group 3 which differed, mineralogically, from the other groups by the presence of biotite in the sand and more illite in the silt and clay fractions. Otherwise all samples were quite similar in mineral composition, with montmorillonite the predominant clay mineral.The source of some of the soils of Southern Saskatchewan and Southern Alberta has generally been attributed to the Bearpaw formation. This view is supported by the present study.
A STUDY OF THE MINERALOGICAL COMPOSITION OF SAND IN SOUTHERN ONTARIO
Authors: Dell Carol I.
Published: March 2010

A mineralogical study of the fine sand fraction of unweathered tills and stratified sands chosen to represent the deposits of the major ice lobes of southern Ontario was carried out. In addition, a few analyses were made of the coarse silt and coarser sands.In general there was the same variety of minerals in all samples and they varied only in their proportions. Tills overlying Palaeozoic bedrock contained abundant carbonates and shale fragments constituting up to 70 per cent of some fine sands. In the coarse sands, carbonates and shale increased sharply. In the coarse silt and fine sand, feldspars were more abundant than quartz whereas in the medium and coarse sand the reverse was true. Quartz increased in quantity with increasing grain size and reached a maximum in the medium sand. Heavy minerals usually constituted less than 15 per cent of the fine sand. Some of the minerals present in the coarse silt and fine sand were not found in the coarser sands. Usually the order of abundance of the heavy minerals was: hornblende, garnet, micas, magnetite, pyroxenes and sphene. Epidote, rutile, apatite, tourmaline, staurolite, kyanite and others were also noted. A chart listing the plant nutrient elements found in these minerals was prepared.
QUANTITATIVE MANOMETRIC DETERMINATION OF CALCITE AND DOLOMITE IN SOILS AND LIMESTONES
Authors: Skinner S. I. M. , Halstead R. L. , Brydon J. E.
Published: March 2010

The determination is based on the difference in rates of solution of calcite and dolomite. The CO2 evolved from reaction of a mixture of calcite and dolomite in excess HCl is measured at frequent intervals until the reaction is completed. The logarithm of the amount of CO2 equivalent to unreacted carbonate is plotted against time. Following the rapid and complete solution of calcite, the curve for dolomite assumes a much smaller slope and is linear for a period of time. Extrapolation of this linear portion of the curve to zero time gives the amount of CO2 equivalent to the dolomite initially present. The CO2 from calcite is obtained by difference from the total CO2. The amounts of calcite and dolomite found in a number of prepared mixtures by this intercept method were in good agreement with the amounts known to be present. Several samples of limestone and calcareous soil were analysed by the proposed method and the results were compared with X-ray diffraction and chemical data.
AN IN-SITU TECHNIQUE FOR THE QUANTITATIVE DETERMINATION OF FERTILIZER PHOSPHORUS IN GROWING PLANTS
Authors: Miller M. H. , Werkhoven C. H. E.
Published: March 2010

A technique is presented which permits the quantitative estimation of fertilizer phosphorus in plants at any desired time during the growth cycle without harvesting the plants. The radioactivity of the growing plants was determined in situ by a thin-walled aluminum Geiger-Mueller tube assembly. The in-situ activity was found to be highly correlated with the fertilizer-phosphorus content (mg./pot) at any one stage of growth of oats (r = 0.975), corn (r = 0.966), and sugar beets (r = 0.813). The relationship between the in-situ activity and the fertilizer-phosphorus content varied with plant height. Regression equations are presented relating the fertilizer-phosphorus content to the in-situ activity and plant height. Correlation coefficients for the regression equations were 0.943, 0.914, and 0.902 for oats, corn, and sugar beets respectively. The coefficient of variation of the fertilizer-phosphorus content of sugar beets using the regression equation was 15.3 per cent, whereas that using the briquet technique was 16.1 per cent.
THE OCCURRENCE OF CHLORITE AND VERMICULITE IN THE CLAY FRACTION OF THREE BRITISH COLUMBIA SOILS
Authors: Theisen A. A. , Webster G. R. , Harward M. E.
Published: March 2010

The clay mineralogy of surface samples from three soils on Vancouver Island which had been used in fertility experiments was determined by X-ray diffraction. Chlorite was identified as the predominant mineral in all three soils. Vermiculite was present in discrete units in the Chemainus soil and interstratified with chlorite in the Fairbridge and Merville soils. Kaolinite may also have been a constituent; this could not be determined since the use of certain criteria, proposed in the past for the identification of kaolinite in the presence of chlorite, proved unsuccessful. It was concluded that no universal criterion, which holds true in all cases, exists for distinguishing kaolinite in the presence of chlorite.
EFFECT OF DRYING ON EXCHANGEABLE POTASSIUM OF ONTARIO SOILS AND THE RELATION OF EXCHANGEABLE POTASSIUM TO CROP YIELD
Authors: Matthews B. C. , Sherrell C. G.
Published: March 2010

Exchangeable potassium in field moist, air-dry and oven-dry samples of surface soil of 15 soil types was extracted with 0.1 N ammonium acetate. It was found that, if the per cent potassium saturation of the cation exchange capacity was 1.11 ± 0.12, no change in the amount of exchangeable potassium occurred during drying of the soil. Above this equilibrium per cent potassium saturation, the exchangeable potassium was decreased by drying, and below this per cent saturation exchangeable potassium was increased by drying.The degree of correlation of exchangeable potassium at each of the different soil moisture contents with yields, i.e. Log (100 – % yield), of wheat, oats, and corn in the field was not affected by the drying treatment. Moreover, the exchangeable potassium level accounted for a relatively small part of the yield variability of these crops. For potatoes, however, there was a highly significant correlation between exchangeable potassium at each soil moisture content and yield, i.e. Log (100 – % yield) and the correlation coefficient was highest for the oven-dried soil.The degree of correlation between per cent potassium saturation at the different soil moisture contents with crop yield was not significant for any of the four crops.
THE PERSISTENCE OF CERTAIN PESTICIDES IN THE SOIL AND THEIR EFFECT ON CROP YIELDS
Authors: MacPhee A. W. , Chisholm D. , MacEachern C. R.
Published: March 2010

From 1954 to 1958 at Kentville, Nova Scotia, the persistence and residual effects of certain pesticides, added to the soil annually from 1949 to 1953 inclusive, were investigated. Stability of pesticides in the soil rated in descending order of persistency was as follows: arsenic, DDT, BHC, chlordane. Arsenic, DDT, and sulphur caused decreases in the yields of some crops. Evidence indicated that DDT, BHC, and parathion were translocated to root crops. Increased concentrations of arsenic in the soil resulted in increased accumulations of the element in plants.The use of lime in the soil did not ameliorate the toxic conditions resulting from the arsenic and DDT treatments, but did correct the effects of sulphur applications.
EFFECTS OF DIFFERENT CROPPING SYSTEMS AND OF A SOIL CONDITIONER (VAMA) ON SOME SOIL PHYSICAL PROPERTIES AND ON GROWTH OF TOMATOES
Authors: Doyle J. J. , Hamlyn F. G.
Published: March 2010

Soil physical condition resulting from different cropping systems was examined on a number of New Brunswick soils and compared with that of the adjoining soils which had been under continuous grass.Continuous cropping to potatoes reduced the percentage of water-stable aggregates and porosity. Other effects of continuous cultivation were a reduction in soil organic matter content, available water capacity and cation exchange capacity.VAMA (soil conditioner) increased the percentage of water-stable aggregates and the porosity of the cultivated soils. On the continuous-grass soils these properties were not affected. Other effects of VAMA were an increase in cation exchange capacity and a reduction in available water capacity on all soils.Yields of tomatoes in the greenhouse were lower on the soils which had been cropped continuously to potatoes than on the corresponding soils which had been under continuous grass. VAMA increased yields of tomatoes on the continuous-potato soils. The increase in yield due to VAMA was directly related to increase in percentage of water-stable aggregates and total pore space.
EFFECT OF IRRIGATION INTERVAL ON PEAK FLOW REQUIREMENTS IN SPRINKLER IRRIGATED ORCHARDS
Authors: Wilcox J. C.
Published: March 2010

Correlations were calculated between the peak flow of water per acre delivered to 174 orchards in the Okanagan Valley in 1958 and the irrigation interval used—that is, the interval between the start of one irrigation and the start of the next irrigation at the same location. Orchards were omitted where seepage water or wilting was in evidence. High negative correlations were obtained between irrigation interval and peak flow. It is concluded that the smaller the field capacity of the soil for moisture, and hence the shorter the irrigation interval, the greater is the required flow of water per acre. This is attributed to greater wastage of water with coarse-textured soils than with fine-textured soils. Some of this wastage is considered to be unavoidable.
NOTE ON AN APPARATUS FOR CONTROLLING SOIL TEMPERATURES
Authors: COOPER D. J. , NEILSEN K. F. , WHITE J. W. , KALBFLEISCH W.
Published: March 2010

not available
NOTE ON A FERTILIZER PLACEMENT SEEDER
Authors: NYBORG M. , STOKER J. G.
Published: March 2010

not available
A STATISTICAL COMPARISON OF LABORATORY METHODS OF DETERMINING THE PERMANENT WILTING POINT OF SOIL
Authors: WILCOX J. C.
Published: March 2010

not available
THE EFFECT OF DRAINAGE CONDITION ON THE REDOX POTENTIAL, LEACHATE COMPOSITION AND MORPHOLOGICAL CHARACTERISTICS OF A SOIL PARENT MATERIAL STUDIED IN THE LABORATORY
Authors: McKeague J. A. , Bentley C. F.
Published: March 2010

Plastic columns containing a calcareous clay loam soil parent material with and without ground aspen leaves at the surface were maintained under different drainage conditions for 32 months. Distilled water was added at regular intervals. Results of redox potential (Eh) measurements at four depths, leachate analysis and analysis of the soil material are presented.With water table to the surface and a layer of surface leaves, low Eh readings and appreciable iron movement resulted. In a column with fluctuating water table and surface leaves, raising the water table brought about a decrease in the Eh of the soil below the water table. Height of water table had no effect on the Eh of a column which had no leaves at the surface. In columns where the soil material was mixed with quartz sand, leaching brought about marked downward movement of silt and clay size particles. Apart from the removal of soluble salts, there was little measurable change in columns which had no admixture of sand.
THE INFLUENCE OF FERTILIZER PLACEMENT AND RATE OF NITROGEN ON FERTILIZER PHOSPHORUS UTILIZATION BY OATS AS STUDIED USING A CENTRAL COMPOSITE DESIGN
Authors: Miller M. H. , Ashton G. C.
Published: March 2010

A greenhouse study was conducted to determine the optimum fertilizer phosphorus placement for oats and to determine the influence of nitrogen rate on the absorption of fertilizer phosphorus. A central composite design in three variables was used to permit the development of quadratic equations to express the response criteria as functions of the placement variables — horizontal distance and depth from the seed — and rate of nitrogen.The fertilizer phosphorus absorption was determined at four stages of growth, the last stage being 58 days after planting. The dry weight of tops, total phosphorus content and per cent of the phosphorus derived from the fertilizer were determined at the completion of the experiment 58 days after planting.At the 14-day stage fertilizer phosphorus absorption was greatest from fertilizer placed with the seed but, at the 28- and 42-day stages, was greatest from fertilizer placed 1 inch to the side and 2 or 3 inches below the seed. At the 58-day stage, fertilizer placed with the seed resulted in the greatest absorption of fertilizer phosphorus. The influence of placement on the per cent of the plant phosphorus that was derived from the fertilizer was similar to that on fertilizer phosphorus absorption.Nitrogen increased fertilizer phosphorus absorption at all but the 14-day stage, increased plant weight to a lesser extent and decreased the per cent phosphorus in the tops at the 58-day stage.
COMPOSITE DESIGNS IN AGRICULTURAL RESEARCH
Authors: Robinson P. , Nielsen K. F.
Published: March 2010

An experiment was conducted in the greenhouse using tomato plants for testing response to nitrogen, phosphorus and potassium on North Gower clay loam and Castor silt loam.Two designs were used to assess this response, a factorial and a composite design. There was general over-all agreement in results obtained by the two methods. The limitations of the composite design and difficulty in interpretation are discussed.It is suggested that composite designs be used in agricultural research with some caution. With only three factors under test, the standard factorial is preferred.
EFFECTS OF SAWDUST USED AS A MULCH AND AS A SOIL AMENDMENT ON SOIL TEMPERATURES UNDER IRRIGATED AND UNIRRIGATED CONDITIONS
Authors: Webster G. R. , Adamson R. M.
Published: March 2010

Soil temperature readings were taken at 7.30 a.m., noon, and 5 p.m. over a 3-year period (2 years without and 1 year with irrigation) at a point 4 inches below the surface of sawdust-mulched, sawdust-incorporated and check plots. The effect of blackened sawdust mulch on soil temperatures was also studied. Marked differences between soil temperatures in the various treatments were found, the greatest being during July when the difference between the average maximum and minimum air temperature was also greatest. Soil temperatures were lower in the sawdust-mulched than in the check plots, except at 7.30 a.m. under irrigation when readings were higher throughout the season in the mulched plot. After August under irrigated conditions and after October without irrigation a reversal took place, and the soil temperatures became higher under the mulch than in the check due to the slower heat loss from the mulched soil. Incorporating sawdust had only a slight effect upon soil temperatures, but blackening the mulch markedly reduced the soil temperature differences between mulched and unmulched treatments.
AN INVESTIGATION OF THE INTERCEPT METHOD FOR DETERMINING THE PROPORTION OF DOLOMITE AND CALCITE IN MIXTURES OF THE TWO: I. Theoretical aspects of the rate of solution of dolomite when a number of crystals are present
Authors: Turner R. C.
Published: March 2010

The nature of the log V vs. t plot, representing the rate of solution of dolomite consisting of a number of crystals, has been analysed theoretically. The plot may be concave either upwards or downwards, depending on the size distribution of the crystals. Nevertheless, the deviations from linearity, during the time required to dissolve about 50 per cent of the smallest crystal, are always within limits. These limits are calculated and their significance in relation to the line of best fit is discussed.
Significance of Travel to Rural Areas as a Risk Factor for Malarial Anemia in an Urban Setting
Authors: Siri Jose G. , Wilson Mark L. , Murray Susan , Rosen Daniel H. , Vulule John M. , Slutsker Laurence , Lindblade Kim A.
Published: March 2010

The epidemiology of malaria in urban environments is poorly characterized, yet increasingly problematic. We conducted an unmatched case–control study of risk factors for malarial anemia with high parasitemia in urban Kisumu, Kenya, from June 2002 through February 2003. Cases (n = 80) were hospital patients with a hemoglobin level ≤ 8 g/dL and a Plasmodium parasite density ≥ 10,000/μL. Controls (n = 826) were healthy respondents to a concurrent citywide knowledge, attitude, and practice survey. Children who reported spending at least one night per month in a rural area were especially at risk (35% of cases; odds ratio = 9.3, 95% confidence interval [CI] = 4.4–19.7, P < 0.0001), and use of mosquito coils, bed net ownership, and house construction were non-significant, potentially indicating that malaria exposure during rural travel comprises an important element of risk. Control of severe malaria in an urban setting may be complicated by Plasmodium infections acquired elsewhere. Epidemiologic studies of urban malaria in low transmission settings should take travel history into account.
Myocarditis during Acute Schistosomiasis in Two Travelers
Authors: Epelboin Loïc , Jauréguiberry Stéphane , Estève Jean-Baptiste , Danis Martin , Komajda Michel , Bricaire François , Caumes Eric
Published: March 2010

We report two cases of myocarditis complicating acute schistosomiasis in returning travelers. Treatment with corticosteroids led to full recovery in both cases. Although the pathophysiology of this complication remains unclear, we recommend treating such patients with corticosteroids rather than praziquantel, which can be associated with clinical deterioration.
Comparison of Elastography, Serum Marker Scores, and Histology for the Assessment of Liver Fibrosis in Hepatitis B Virus (HBV)-Infected Patients in Burkina Faso
Authors: Bonnard Philippe , Sombié Roger , Lescure Francois-Xavier , Bougouma Alain , Guiard-Schmid Jean Baptiste , Poynard Thierry , Calès Paul , Housset Chantal , Callard Patrice , Pendeven Catherine Le , Drabo Joseph , Carrat Fabrice , Pialoux Gilles
Published: March 2010

Liver fibrosis (LF) must be assessed before talking treatment decisions in hepatitis B. In Burkina Faso, liver biopsy (LB) remains the “gold standard” method for this purpose. Access to treatment might be simpler if reliable alternative techniques for LF evaluation were available. The hepatitis B virus (HBV)-infected patients who underwent LB was invited to have liver stiffness measurement (Fibroscan) and serum marker assays. Fifty-nine patients were enrolled. The performance of each technique for distinguishing F0F1 from F2F3F4 was compared. The area under receiver operating characteristic (AUROC) curves was 0.61, 0.71, 0.79, 0.82, and 0.87 for the aspartate transaminase to platelet ratio index (APRI), Fib-4, Fibrotest, Fibrometre, and Fibroscan. Elastometric thresholds were identified for significant fibrosis and cirrhosis. Combined use of Fibroscan and a serum marker could avoid 80% of biopsies. This study shows that the results of alternative methods concord with those of histology in HBV-infected patients in Burkina Faso. These alternative techniques could help physicians to identify patients requiring treatment.
Urban Transmission of American Cutaneous Leishmaniasis in Argentina: Spatial Analysis Study
Authors: Gil José F. , Nasser Julio R. , Cajal Silvana P. , Juarez Marisa , Acosta Norma , Cimino Rubén O. , Diosque Patricio , Krolewiecki Alejandro J.
Published: March 2010

We used kernel density and scan statistics to examine the spatial distribution of cases of pediatric and adult American cutaneous leishmaniasis in an urban disease-endemic area in Salta Province, Argentina. Spatial analysis was used for the whole population and stratified by women > 14 years of age (n = 159), men > 14 years of age (n = 667), and children < 15 years of age (n = 213). Although kernel density for adults encompassed nearly the entire city, distribution in children was most prevalent in the peripheral areas of the city. Scan statistic analysis for adult males, adult females, and children found 11, 2, and 8 clusters, respectively. Clusters for children had the highest odds ratios (P < 0.05) and were located in proximity of plantations and secondary vegetation. The data from this study provide further evidence of the potential urban transmission of American cutaneous leishmaniasis in northern Argentina.
Diagnosis of Scrub Typhus
Authors: Koh Gavin C. K. W. , Maude Richard J. , Paris Daniel H. , Newton Paul N. , Blacksell Stuart D.
Published: March 2010

Scrub typhus is transmitted by trombiculid mites and is endemic to East and Southeast Asia and Northern Australia. The clinical syndrome classically consists of a fever, rash, and eschar, but scrub typhus also commonly presents as an undifferentiated fever that requires laboratory confirmation of the diagnosis, usually by indirect fluorescent antibody (IFA) assay. We discuss the limitations of IFA, debate the value of other methods based on antigen detection and nucleic acid amplification, and outline recommendations for future study.
Under Treated Necrotizing Fasciitis Masquerading as Ulcerated Edematous Mycobacterium ulcerans Infection (Buruli Ulcer)
Authors: Phanzu Mavinga D. , Bafende Aombe E. , Imposo Bofunga B. D. , Meyers Wayne M. , Portaels Françoise
Published: March 2010

We report a case of under treated necrotizing fasciitis (NF) in a 65-year-old woman with diabetes misdiagnosed as Mycobacterium ulcerans infection. She came to the Institut Médical Evangélique (IME) with an extensive painful edematous ulcerated lesion on the dorsum of the right foot and ankle. The diagnosis of Buruli ulcer (BU) was based initially on clinical findings and place of residence (Songololo Territory, the largest known focus of BU in Bas-Congo province). Tissue specimens gave negative results for acid-fast bacilli (AFB), culture, and polymerase chain reaction (PCR) for M. ulcerans. Histopathologic analysis revealed marked necrosis of the lower dermis and subcutaneous tissue. No AFB was found. Later, scattered foci of intracellular gram-positive cocci typical of streptococci were seen. Clinicopathologic correlation of these findings strongly supported the diagnosis of NF. This patient shows the difficulties that may be encountered even in known endemic areas in recognizing BU cases purely on clinical findings.
Primary Super-Infection of Hydatid Cyst—Clinical Setting and Microbiology in 37 Cases
Authors: García Moncef Belhassen , Lledías Javier Pardo , Pérez Inmaculada Galindo , Tirado Virginia Velasco , Pardo Lucia Fuentes , Bellvís Luis Muñoz , Varela Gonzalo , Sánchez Miguel Cordero
Published: March 2010

The clinical and microbiological characteristics of super-infected hydatid cysts are described. In our cohort, 7.3% of 503 patients had a super-infected cyst. Four patients developed severe sepsis, and two of them died. Escherichia coli, viridans group streptococci, and Enterococcus species in liver cysts and Aspergillus fumigatus in lung cysts were the microorganisms most frequent involved.
The SYBR Green I Malaria Drug Sensitivity Assay: Performance in Low Parasitemia Samples
Authors: Vossen Matthias G. , Pferschy Sandra , Chiba Peter , Noedl Harald
Published: March 2010

Validation of the sensitivity of the SYBR Green I in vitro test against an enzyme-linked immunosorbent assay (ELISA)-based drug sensitivity assay. Our results suggest that the SYBR Green I assay is a fast and inexpensive malaria drug screening assay for laboratory use. However, because of its lack of sensitivity in whole blood samples its usefulness for testing clinical samples may be limited.
Predicting Potential Risk Areas of Human Plague for the Western Usambara Mountains, Lushoto District, Tanzania
Authors: Neerinckx Simon , Peterson A. Townsend , Gulinck Hubert , Deckers Jozef , Kimaro Didas , Leirs Herwig
Published: March 2010

A natural focus of plague exists in the Western Usambara Mountains of Tanzania. Despite intense research, questions remain as to why and how plague emerges repeatedly in the same suite of villages. We used human plague incidence data for 1986–2003 in an ecological-niche modeling framework to explore the geographic distribution and ecology of human plague. Our analyses indicate that plague occurrence is related directly to landscape-scale environmental features, yielding a predictive understanding of one set of environmental factors affecting plague transmission in East Africa. Although many environmental variables contribute significantly to these models, the most important are elevation and Enhanced Vegetation Index derivatives. Projections of these models across broader regions predict only 15.5% (under a majority-rule threshold) or 31,997 km2 of East Africa as suitable for plague transmission, but they successfully anticipate most known foci in the region, making possible the development of a risk map of plague.
Different Lineages of Chikungunya Virus in Equatorial Guinea in 2002 and 2006
Authors: Collao Ximena , Negredo Ana I. , Cano Jorge , Tenorio Antonio , Ory Fernando de , Benito Agustin , Masia Mar , Sánchez-Seco María-Paz
Published: March 2010

Chikungunya virus is a mosquito-borne virus that causes an acute febrile infection and severe arthralgia and is considered a re-emergent pathogen. During a study investigating arboviruses causing febrile infection in infants in Bata, Equatorial Guinea, the genome of this virus was amplified from blood samples during near two rainy seasons (2002–2003). In 2006, this virus was isolated from a traveler returning to Spain from Equatorial Guinea. These results show that chikungunya virus is present in this country and two lineages are circulating. Thus, this virus should be considered in the differential diagnosis of febrile syndromes in inhabitants and in travelers returning from this country.
Risk Factors for Acute Kidney Injury in Visceral Leishmaniasis (Kala-Azar)
Authors: Oliveira Michelle J. C. , Silva Júnior Geraldo B. , Abreu Krasnalhia Lívia S. , Rocha Natália A. , Garcia Ana Valeska V. , Franco Luiz F. L. G. , Mota Rosa M. S. , Libório Alexandre B. , Daher Elizabeth F.
Published: March 2010

The aim of this study was to investigate the factors associated with acute kidney injury (AKI) in patients with visceral leishmaniasis (VL). The study patients had a diagnosis of VL and were admitted to a tertiary hospital. A multivariate analysis was performed to analyze the risk factors for AKI. A total of 224 patients were included. The mean age was 36 ± 15 years. AKI was observed in 33.9% of cases. Risk factors associated with AKI were male gender (odds ratio [OR] = 2.2; P = 0.03), advanced age (OR = 1.05; P < 0.001), and jaundice (OR = 2.9; P = 0.002). There was an association between amphotericin B use and AKI (OR = 18.4; P < 0.0001), whereas glucantime use was associated with lower incidence of AKI compared with amphotericin B use (OR = 0.05; P < 0.0001). Mortality was 13.3%, and it was higher in AKI patients (30.2%). Therefore, factors associated with AKI were male gender, advanced age, and jaundice. Amphotericin B was an important cause of AKI in VL.
A Controlled Trial to Assess the Effect of Quinine, Chloroquine, Amodiaquine, and Artesunate on Loa loa Microfilaremia
Authors: Kamgno Joseph , Djomo Patrick Nguipdop , Pion Sébastien D. , Thylefors Björn , Boussinesq Michel
Published: March 2010

Onchocerciasis control is currently based on mass ivermectin treatment. Unfortunately, this drug can induce serious adverse events (SAEs) in persons with high levels of Loa loa microfilaremia (> 30,000 microfilaria/mL). A means of preventing SAEs would be to treat at risk populations with a drug that would progressively reduce the microfilarial loads before administering ivermectin. Antimalarial drugs are a potential solution because they have shown some activity against various filarial species. A controlled trial was conducted to assess the effect of standard doses of quinine, chloroquine, amodiaquine, and artesunate on L. loa microfilaremia. Ninety-eight patients were randomly allocated into five groups (one for each drug and a control group) after stratification on microfilarial load. Loa loa microfilaremia was monitored on days 0, 3, 7, 15, 30, 60, and 90. No significant change in the loads was recorded in any of the treatment groups. A comprehensive review of the effects of antimalarial drugs against filariae is also provided.
Annual Burden of Ocular Toxoplasmosis in the United States
Authors: Jones Jeffrey L. , Holland Gary N.
Published: March 2010

Toxoplasmosis is the most common retinal infection in the United States, and it can severely impact vision. We used data from population-based studies, outbreaks, and the U.S. census to estimate the burden of Toxoplasma gondii infection and ocular toxoplasmosis. We estimate that 1,075,242 persons are infected with T. gondii, 21,505 persons have ocular lesions (both asymptomatic and symptomatic), and 4,839 (range = 2,150–7,527) persons develop symptomatic ocular toxoplasmosis each year in the United States. Toxoplasmosis contributes a significant burden to eye disease in the United States.
PLGA nanocapsules as a delivery system for a recombinant LRP‐based therapeutic
Authors: Bernert Martin , Bignoux Monique J. , Madhav Chandni , Gqeba Sichumiso , Otgaar Tyrone C. , Morris Gavin , Weiss Stefan F. T. , Ferreira Eloise
Published: May 2024

Telomerase activity is directly affected by the laminin receptor precursor (LRP) protein, a highly conserved nonintegrin transmembrane receptor, which has been shown to have therapeutic effects in ageing, and age‐related diseases. Recently, it has been found that overexpression of LRP‐FLAG, by plasmid transfection, leads to a significant increase in telomerase activity in cell culture models. This may indicate that upregulation of LRP can be used to treat various age‐related diseases. However, transfection is not a viable treatment strategy for patients. Therefore, we present a nanoencapsulated protein‐based drug synthesised using poly(lactic‐co‐glycolic acid) (PLGA) nanocapsules for delivery of the 37 kDa LRP protein therapeutic. PLGA nanocapsules were synthesised using the double emulsification‐solvent evaporation technique. Different purification methods, including filtration and centrifugation, were tested to ensure that the nanocapsules were within the optimal size range, and the BCA assay was used to determine encapsulation efficiency. The completed drug was tested in a HEK‐293 cell culture model, to investigate the effect on cell viability, LRP protein levels and telomerase activity. A significant increase in total LRP protein levels with a concomitant increase in cell viability and telomerase activity was observed. Due to the observed increase in telomerase activity, this approach could represent a safer alternative to plasmid transfection for the treatment of age‐related diseases.
Adaptive dynamic programming and distributionally robust optimal control of linear stochastic system using the Wasserstein metric
Authors: Liang Qingpeng , Hu Jiangping , Xiang Linying , Shi Kaibo , Wu Yanzhi
Published: May 2024

In this paper, we consider the optimal control of unknown stochastic dynamical system for both the finite‐horizon and infinite‐horizon cases. The objective of this paper is to find an optimal controller to minimize the expected value of a function which depends on the random disturbance. Throughout this paper, it is assumed that the mean vector and covariance matrix of the disturbance distribution is unknown. An uncertainty set in the space of mean vector and the covariance matrix is introduced. For the finite‐horizon case, we derive a closed‐form expression of the unique optimal policy and the opponents policy that generates the worst‐case distribution. For the infinite‐horizon case, we simplify the Riccati equation obtained in the finite‐hozion setting to an algebraic Riccati equation, which can guarantee the existence of the solution of the Riccati equation. It is shown that the resulting optimal policies obtained in these two cases can stabilize the expected value of the system state under the worst‐case distribution. Furthermore, the unknown system matrices can also be explicitly computed using the adaptive dynamic programming technique, which can help compute the optimal control policy by solving the algebraic Riccati equation. Finally, a simulation example is presented to demonstrate the effectiveness of our theoretical results.
Phase Evolution of Multi‐Metal Dichalcogenides With Conversion‐Alloying Hybrid Mechanism for Superior Lithium Storage
Authors: Jiang Jingjing , Hu Sanlue , Zhang Xiangyong , Li Senlin , Wei Hua , Ren Baohui , Li Shizhen , Chen Guangming , Yang Jinlong , Han Cuiping , Liu Zhuoxin
Published: May 2024

Traditional lithium‐ion battery (LIB) anodes, whether intercalation‐type like graphite or alloying‐type like silicon, employing a single lithium storage mechanism, are often limited by modest capacity or substantial volume changes. Here, the kesterite multi‐metal dichalcogenide (CZTSSe) is introduced as an anode material that harnesses a conversion‐alloying hybrid lithium storage mechanism. Results unveil that during the charge–discharge processes, the CZTSSe undergoes a comprehensive phase evolution, transitioning from kesterite structure to multiple dominant phases of sulfides, selenides, metals, and alloys. The involvement of multi‐components facilitates electron transport and mitigates swelling stress; meanwhile, it results in formation of abundant defects and heterojunctions, allowing for increased lithium storage active sites and reduced lithium diffusion barrier. The CZTSSe delivers a high specific capacity of up to 2266 mA h g−1 at 0.1 A g−1; while, maintaining a stable output of 116 mA h g−1 after 10 000 cycles at 20 A g−1. It also demonstrates remarkable low‐temperature performance, retaining 987 mA h g−1 even after 600 cycles at −40 °C. When employed in full cells, a high specific energy of 562 Wh kg−1 is achieved, rivalling many state‐of‐the‐art LIBs. This research offers valuable insights into the design of LIB electrodes leveraging multiple lithium storage mechanisms.