Higher Nitrogen Values Research Articles

Multi-isotope analysis of the population of the lost medieval village of Auldhame, East Lothian, Scotland

This study is one of only a handful to combine strontium, oxygen, carbon, nitrogen and sulphur isotope data for medieval human remains, in this case from individuals buried in a cemetery in the remote Scottish coastal village of Auldhame, which was abandoned in the 17th century AD. The strontium and oxygen isotope analysis of tooth enamel suggests that the group predominantly comprised a local, static population and thus this allows the examination of the dietary habits of a remote coastal community. The combination of relatively high nitrogen isotope values with relatively low carbon isotope values within bone collagen suggests little marine protein in the diet, which is unusual given the coastal location. The community may have been consuming some freshwater fish or omnivores (pigs fed on animal diets), but also we suggest that the combination of isotope values could be explained by soil improvement methods. Some evidence for soil deepening at the site, and by association manuring, suggests that the consumption of cereals was important to the diet, and may explain the high nitrogen values found in combination with terrestrial carbon isotope values. This combination of dietary isotopes has previously been suggested to be unusual for the medieval period, but we propose it is perhaps more common than originally conceived. As there are few previous multi-isotope studies from Scottish medieval assemblages on this scale, the study provides an opportunity to construct a picture of medieval and early post-medieval life in rural Scotland.

Low-Temperature Halo-Carbon Homoepitaxial Growth of 4H-SiC: Morphology, Doping, and Role of HCl Additive

Low-temperature epitaxial growth of 4H-SiC with CH3Cl carbon precursor was further developed. In-situ doping with nitrogen and aluminum was investigated. The nitrogen concentration in epitaxial layers grown on the C face was almost two orders of magnitude higher than that in the Si-face epilayers grown in the same growth run at 13000C. The opposite trend was observed for intentional aluminum doping, with more than an order of magnitude higher aluminum concentration incorporated in Si-face epilayers. High values of nitrogen and aluminum doping well in excess of 1020 cm-3 without any obvious epilayer morphology degradation can be achieved on C-face and Siface respectively. Addition of HCl during halo-carbon growth at 13000C resulted in drastic improvement of the surface morphology. Also, a significant increase of the growth rate took place confirming that the improvement in the epilayer morphology during HCl-assisted growth is predominantly related to silicon cluster etching by additional Cl-containing vapor species.

Melanized halophilic fungi are eukaryotic members of microbial communities in hypersaline waters of solar salterns

Until recently, it was believed that microbial communities at high salinities are dominated exclusively by Archaea and Bacteria and one eukaryotic species, the alga Dunaliella salina. Recently, it became evident that melanized fungi, so far described only in the crystallization pond of Adriatic salterns within the season of salt production, can be considered as a new group of eukaryotic halophiles. They were represented by black, yeast-like hyphomycetes: Hortaea werneckii, Phaeotheca triangularis, Trimmatostroma salinum, Aureobasidium pullulans, together with phylogenetically closely related Cladosporium species. In the present study, the distribution of the melanized fungal population in five different evaporating ponds in the Adriatic salterns wcovering the entire salinity range (3–30% NaCl)x was followed throughout the year. It appeared in three peaks, at 5–8%, 10–20% and 18–25% NaCl, which correlated primarily with high nitrogen values. At the highest environmental salinities, melanized fungi represented 85–100% of the total isolated mycobiota, but with lowering salinities they were partially replaced by non-melanized fungi and, at the end of the season, with NaCl concentrations below 5%, they were detected only occasionally. Melanized fungi have been isolated from hypersaline waters on three continents, indicating that they are present globally in hypersaline waters of man-made salterns.

Hydrophysical and hydrobiological processes in the Gulf of Finland in summer 1987: characterization and relationship

On the basis of repeated CTD surveys and current measurements in June–July 1987 the generation and development of wind-induced upwelling (near the northern) and downwelling (near the southern) coasts, together with frontal zones caused by coastal water offshore transport, were observed. Strong coastal currents parallel to the coast occurred, together with downwelling near the southern coast of the Gulf of Finland. The formation of a “tongue-like” water mass with a sharp thermohaline “front” (TLF) was observed to extend from the southern coast, after the wind conditions changed. Hydrochemical and hydrobiological parameters were studied in both the upwelling and TLF, exposing the changes in biological parameters at different trophic levels in the fronts of different types. Higher values of nutrients, chlorophyll a content and primary production in the upwelling frontal zone were caused by the upwelled water. The increase in primary production in the surface layer within the upwelling area was caused by nutrient transport from the deeper layers, expressed only in the higher values of nitrogen. The absence of an increase in phosphorus, the limiting factor for primary production, can be explained by the high consuming rate. In the TLF, no increase in nutrients and only a slight increase in primary production took place. The increase in abundance of young herring and zooplankton in the TLF was caused by the distribution of the hydrophysical parameters. These organisms of the higher trophic level were carried by offshore currents, together with the less saline and warmer coastal waters. The increase in abundance of the young herring near the TLF is related also to the best feeding conditions near the front. It is concluded that temperature and salinity fronts are associated with changes in biological parameters of different trophic levels, depending upon the mechanisms of formation of the front.

Nuclear techniques for finding chemical explosives in airport luggage

Chemical explosives are composed of concentrated densities of nitrogen and oxygen. High values of the nitrogen alert the presence of a bomb; high values of both nitrogen and oxygen densities certify the bomb's presence uniquely. More than a dozen nuclear-based techniques have been proposed for rapidly scanning airport luggage to find hidden explosives by measuring these elemental distributions. In almost every scheme, the technological challenge is the accelerator, which must be small, well-shielded, cost-effective, and be operable in busy airports by nominally-trained personnel, with minimum unscheduled downtime for repairs or service. This paper will summarize, within the limits imposed by security, four of the imaging schemes.

Tissue constituents of reptiles in relation to their mode of life—III. Nitrogen content and serum proteins

1. 1. Nitrogen content of different tissues was determined in Crocodilus niloticus, Tropidonotus tessellatus, Chalcides ocellatus, Varanus griseus and Testudo leithii. Serum proteins of the same animals with the exception of C. ocellatus were also determined. 2. 2. The nitrogen content of tissues of any species varies according to the type of the tissue while it is more or less constant in the different individuals of the same species. 3. 3. Tissues with high water content (calculated on fat-free basis) possess low content of nitrogen and vice versa. 4. 4. Tissues of aquatic reptiles possess high water content but low lipid and nitrogen contents. 5. 5. Tissues of desert reptiles have low values of water content and high values of nitrogen and lipid contents. 6. 6. No apparent relationship was observed between the concentration of total serum proteins and the habitat of the reptiles examined. 7. 7. The albumin fraction was found to be lower in blood of aquatic reptiles than of semi-desert or desert representatives. The globulin fraction, on the other hand, is higher in blood of aquatic reptiles than in other species. 8. 8. The high albumin fraction in desert reptiles is supposed to induce high colloidal osmotic pressure of the blood and consequently helps it to retain a part of the absorbed water.

Studies on the Specific Soluble Protein of Pasteurella Pestis and Allied Organisms

Summary The specific soluble proteins of virulent and avirulent plague and pseudotuberculosis bacilli were isolated from the filtrates of their growth in casein hydrolysate broth at 28 C for 24 days. The sodium or ammonium sulphate precipitate was found serologically more active than the acetic acid precipitate. Five fractions were isolated from each filtrate by precipitating at one-third, half, half minus one one third, and full minus half saturation of sodium sulphate, the residue being taken as the last fraction. The fraction obtained by half saturation (P½ fraction) was serologically active and formed the bulk (75%) of the precipitate. The rest, including the residue, was serologically inactive. About 90 per cent of the active P½ fraction was constituted by P⅓ fraction (i.e. obtained by one-third saturation with Na2SO4) and the rest by P(½−⅓) fraction, both of which are serologically active. Similar active protein fractions were also isolated from the water soluble extracts of the virulent plague organisms grown on casein hydrolysate agar at 37 C for 72 hours. The P⅓ fraction (called here Lauto P⅓) formed the major bulk (80–90%) of the precipitate reacting with an antiplague horse serum in as high a dilution as 1,280,000. This fraction was found practically absent in the avirulent non-protective strains and completely absent in the pseudotuberculosis strains. Certain chemical physical and serological properties of these protein fractions were studied. Their solubility was found low. The water extractable protein fraction were more soluble and contained higher nitrogen values than those obtained from the broth filtrates. They resembled nucleoprotein in character, but a difference was noted in the tryptophane content of the protein fractions recovered from different organisms. The protein solutions did not give any specific optical rotation but slight differences were noted between virulent and avirulent protective plague strains in the ultraviolet absorption curves. The P⅓ fraction of the virulent and avirulent protective plague strains (called Antigen A) differed serologically from their P(½−⅓) fraction (called Antigen B) as well as from the P⅓ fractions of the non-protective avirulent plague and pseudotuberculosis strains, the latter two fractions behaving almost identically amongst themselves and cross-reacting with the antisera against antigen B and boiled virulent plague organism. It is considered that antigen A is the specific antigen of virulent plague bacillus corresponding to the envelope antigen of Schütze, and that antigen B acts as a common somatic link between the plague and pseudotuberculosis organisms. The antigens A and B are both extractable from both filtrates whereas only antigen A is obtainable from water soluble extracts, the latter providing the most specific soluble antigen of the virulent plague bacillus. An antiserum prepared against this fraction (Lauto P⅓) agglutinates only the protective plague strains to the complete exclusion of the pseudotuberculosis organisms. The results also indicate that there is a progressive deterioration of the virulent plague strains due to subculture until they completely lose the specific antigen A, for the isolation of which a fully nutritive media as provided by the enriched casein hydrolysate broth or agar is necessary. Further work on these protein fractions will be reported later.