Emerging Issues in Infective Endocarditis

Infective endocarditis, a serious infection of the endocardium of the heart, particularly the heart valves, is associated with a high degree of illness and death. It generally occurs in patients with altered and abnormal heart architecture, in combination with exposure to bacteria through trauma and other potentially high-risk activities involving transient bacteremia. Knowledge about the origins of endocarditis stems from the work of Fernel in the early 1500s, and yet this infection still presents physicians with major diagnostic and management dilemmas. Endocarditis is caused by a variety of bacteria and fungi, as well as emerging infectious agents, including Tropheryma whiplei, Bartonella spp., and Rickettsia spp. We review the evolution of endocarditis and compare its progression with discoveries in microbiology, science, and medicine

Atomic Absorption as an Index of the Silver Concentration in Precipitation, Silver Iodide Plume Studies, Part 1

The Perkin Elmbver Model 303, equipped with the DCR-1, digital concentration readout, was evaluated as to its ability to provide an index of silver concentration in water solutions, without concentrating in any manner. The procedures, principal settings, and adjustments which must be observed are described. This instrument can detect the difference between concentrations of 10-15 and 10-12 gm/ml. However, as the concentration of silver decreases the experimental error increases to a point at which the error becomes greater than the differences in readout due to differences in silver concentration

Morphology of the recently re-classified Tasman masked booby (Sula dactylatra tasmani) breeding on the Kermadec Islands

Once thought to be extinct, the Tasman Booby Sula tasmani has recently been re-classified as a subspecies of the Masked Booby S. dactylatra on the basis of genetic data. This re-classification raises the issue of whether this novel clade has a distinct morphology. Morphological differences in size, as well as coloration of integuments, bill and iris have been found in other subspecies of the Masked Booby but have not yet been reported for live Kermadec Islands breeding individuals. Museum specimens from this breeding location have been separated from other Pacific breeding subspecies by their longer wings. We sampled a total of 21 individuals from North Meyer Islet, Kermadec Group, New Zealand, and applied molecular sexing to obtain sex-specific morphometric measurements. We matched dimorphism in vocalization with genetic sexing results and photographic documentation of human-assessed bill, foot and eye coloration. While culmen measurements were consistent with reports from museum specimens, wing chords from living specimens of Tasman Masked Boobies were 3% and 4% larger in males and females, respectively. Females had larger culmens and wings than males, consistent with the low extent of sexual dimorphism reported from museum skins. Adult Tasman Masked Boobies had yellow to buff-yellow feet, while fledglings, as in most sulids, had grey to greyish-yellow feet. Our findings confirm the distinctively long wing and particular iris coloration previously reported for the taxon and provide the first description of integument coloration of live specimens. This study highlights the importance of including in situ assessment in taxon descriptions

The Effect of Carbon Dioxide on Nitrate Accumulation in Carrington Loam

Most microorganisms obtain carbon as well as energy from the oxidation of organic compounds but the nitrifying bacteria assimilate carbon dioxide from the air as a source of carbon. The sulfur bacteria and the hydrogen oxidizing bacteria also assimilate carbon dioxide from the air. Other bacteria that cannot assimilate carbon dioxide from the air are greatly stimulated by its presence. Increasing the concentration of carbon dioxide in the air about cultures of Lactobacillus acidophilus produces higher plate counts and larger colonies than cultures in carbon dioxide-free air. An increased concentration of carbon dioxide in the soil air stimulates the growth of certain of the fungi, particularly those associated with root-rot of the higher plants. Some of the fleshy fungi, the so-called lignin-destroying fungi, are greatly retarded in growth by the removal of carbon dioxide from the atmosphere in which they grow. On the other hand, there are cases on record in which carbon dioxide has acted as a growth depressant or germicide. The spores of Mucor, Aspergillus and Penicillium are prevented from germination by very high concentrations of carbon dioxide. The growth rate of yeast and fermentation of solutions have been retarded by certain concentrations of carbon dioxide

The Effect of Carbon Dioxide on the Yield, Phosphorus and Calcium Contents of Wheat

The concentration of carbon dioxide in the atmosphere is normally about 0.03 per cent but the soil atmosphere usually contains considerably more than this amount especially in the vicinity of roots of rapidly growing plants. The carbon dioxide produced by the plant roots and by microbiological action diffuses from the soil and increases the concentration of carbon dioxide in the atmosphere immediately surrounding the above-ground portions of the plant. It is this carbon dioxide from the soil which the plant utilizes in its growth and hence the significance of an adequate supply is at once apparent. The influence of carbon dioxide on plant growth and on bacterial action in the soil and its effect on the availability of phosphorus and potassium have been studied to some extent but the problem as a whole is far from solved as yet

A Method for Determining the Exchange Capacity of Organic Matter in the Presence of Nitrogen and Calcium

Many methods have been used for determining the base exchange capacity of soils and certain advantages have been claimed by each investigator for his particular method. Fewer studies on the base exchange reactions of organic matter have been made and the nature of the material makes many of the methods used for soils impracticable and inaccurate when applied to organic matter. According to McGeorge (1) the monovalent lignin salts are soluble in alcohol and the use of alcohol in base exchange studies on organic matter is of questionable value. The removal of excess soluble salt from the base exchange complex preparatory to determining the amount of base fixed, by the use of water, allows too great a hydrolysis of monovalent salts and, therefore, will lead to low results. Then again, the monovalent lignin salts are soluble under certain conditions in salt solution, and especially in acetate solutions which hydrolyze and yield OH ions

The Relative Solubility of Soil Phosphorus in Different Solvents

Various investigators have shown that carbon dioxide is important in the soil in making the plant food elements available. As a result attempts have been made to use solvents which are similar to carbon dioxide in their solubility effects on soil phosphorus. In many cases, the available phosphorus as measured by these solvents has correlated rather well with crop responses to phosphate fertilizer in the field, but the correlation is not perfect in all soils

Hydrocarbon Anions in Interstellar Clouds and Circumstellar Envelopes

The recent detection of the hydrocarbon anion C6H- in the interstellar medium has led us to investigate the synthesis of hydrocarbon anions in a variety of interstellar and circumstellar environments. We find that the anion/neutral abundance ratio can be quite large, on the order of at least a few percent, once the neutral has more than five carbon atoms. Detailed modeling shows that the column densities of C6H- observed in IRC +10 216 and TMC-1 can be reproduced. Our calculations also predict that other hydrocarbon anions, such as C4H- and C8H-, are viable candidates for detection in IRC +10 216, TMC-1, and photon-dominated regions such as the Horsehead Nebula