A new type of meteoritic diamond in the enstatite chondrite abee

Diamonds with delta(13)C values of -2 per mil and less than 50 parts per million (by mass) nitrogen have been isolated from the Abee enstatite chondrite by the same procedure used for concentrating Cdelta, the putative interstellar diamond found ubiquitously in primitive meteorites and characterized by delta(13)C values of -32 to -38 per mil, nitrogen concentrations of 2,000 to 12,500 parts per million, and delta(15)N values of -340 per mil. Because the Abee diamonds have typical solar system isotopic compositions for carbon, nitrogen, and xenon, they are presumably nebular in origin rather than presolar. Their discovery in an unshocked meteorite eliminates the possibility of origins normally invoked to account for diamonds in ureilites and iron meteorites and suggests a low-pressure synthesis. The diamond crystals are approximately 100 nanometers in size, are of an unusual lath shape, and represent approximately 100 parts per million of Abee by mass.     

Chondrite barium, neodymium, and samarium isotopic heterogeneity and early Earth differentiation

Isotopic variability in barium, neodymium, and samarium in carbonaceous chondrites reflects the distinct stellar nucleosynthetic contributions to the early solar system. We used 148Nd/144Nd to correct for the observed s-process deficiency, which produced a chondrite 146Sm-142Nd isochron consistent with previous estimates of the initial solar system abundance of 146Sm and a 142Nd/144Nd at average chondrite Sm/Nd ratio that is lower than that measured in terrestrial rocks by 21 +/- 3 parts per million. This result strengthens the conclusion that the deficiency in 142Nd in chondrites relative to terrestrial rocks reflects 146Sm decayand earlyplanetary differentiation processes.     

Air pollution: sensitive detection of ten pollutant gases by carbon monoxide and carbon dioxide lasers

Detection sensitivities of a few parts per billion for ten gaseous pollutants have been evaluated by measuring the strength of the absorption of infrared radiation from carbon monoxide and carbon dioxide lasers. Ethylene concentrations as small as 5 parts per billion have been detected in air. The measured absorption strengths indicate that in mixtures of pollutants, such as nitrogen dioxide and water vapor, the sensitivity is reduced by overlapping absorption bands. However, calculations indicate that it should be possible to detect nitrogen dioxide concentrations of 0.01 part per million in the presence of water vapor concentrations of 105 parts per million.     

Evidence for a late supernova injection of 60Fe into the protoplanetary disk

High-precision 60Fe-60Ni isotope data show that most meteorites originating from differentiated planetesimals that accreted within 1 million years of the solar system's formation have 60Ni/58Ni ratios that are approximately 25 parts per million lower than samples from Earth, Mars, and chondrite parent bodies. This difference indicates that the oldest solar system planetesimals formed in the absence of 60Fe. Evidence for live 60Fe in younger objects suggests that 60Fe was injected into the protoplanetary disk approximately 1 million years after solar system formation, when 26Al was already homogeneously distributed. Decoupling the first appearance of 26Al and 60Fe constrains the environment where the Sun's formation could have taken place, indicating that it occurred in a dense stellar cluster in association with numerous massive stars.     

The organic content of the Tagish Lake meteorite

The Tagish Lake meteorite fell last year on a frozen lake in Canada and may provide the most pristine material of its kind. Analyses have now shown this carbonaceous chondrite to contain a suite of soluble organic compounds (approximately 100 parts per million) that includes mono- and dicarboxylic acids, dicarboximides, pyridine carboxylic acids, a sulfonic acid, and both aliphatic and aromatic hydrocarbons. The insoluble carbon exhibits exclusive aromatic character, deuterium enrichment, and fullerenes containing "planetary" helium and argon. The findings provide insight into an outcome of early solar chemical evolution that differs from any seen so far in meteorites.     

Air containing nitrogen-15 ammonia: foliar absorption by corn seedlings

Thirty-day-old corn seedlings, grown in the greenhouse with different concentrations of supplemental nitrate nitrogen, were moved to a constant-temperature growth chamber and sealed in a 560-liter tent made of polyvinyl chloride. The plants were exposed to air containing ammonia labeled with nitrogen-15 (1, 10, and 20 parts per million) for 24 hours and then harvested. The nitrogen-15 content of the tops and roots showed that at 1 part per million 43 percent of the ammonia was absorbed, whereas at 10 and 20 parts per million, 30 percent of the ammonia was absorbed. The results demonstrate that growing plants may be a natural sink for atmospheric ammonia.     

Butler, missouri: an iron meteorite with extremely high germanium content

The Butler iron meteorite has been found to have a germanium concentration of 2000 parts per million, which is about five times higher than the highest concentration that has been measured previously in an iron meteorite. The gallium concentration is 87 parts per million, which is among the highest concentrations found in these objects. The nickel content is 16.0 percent, the second highest nickel concentration known in a meteorite displaying a Widman st?tten pattern. The high Ge/Ni ratio, as well as the association of a high nickel content with high gallium and germanium contents, make this object an exception to two geochemical generalizations regarding the iron meteorites.     

Mechanisms of nitrogen dioxide reactions: initiation of lipid peroxidation and the production of nitrous Acid

The reactions of nitrogen dioxide with cyclohexene have been studied as a model for the reactions that occur between nitrogen dioxide in smoggy air and unsaturated fatty acids in pulmonary lipids. As predicted from earlier studies at high nitrogen dioxide concentrations, this gas reacts with cyclohexene predominantly by addition to the double bond at nitrogen dioxide concentrations of 1 percent (10,000 parts per million) to 40 percent in nitrogen; in the presence of air or oxygen, this reaction initiates the autoxidation of the alkene. However, at concentrations below 100 parts per million in nitrogen, nitrogen dioxide reacts with cyclohexene almost exclusively by abstraction of allylic hydrogen; this unexpected reaction also initiates the autoxidation of the alkene in the presence of oxygen or air, but it leads to the production of nitrous acid rather than of a product containing a nitro group attached to a carbon atom. The nitrous acid can react with amines to produce nitrosamines. Moreover, the nitrite ion produced by the hydrogen abstraction mechanism would be expected to diffuse throughout the body, unlike nitrated lipids that would be confined to the pulmonary cavity. These findings have been confirmed with methyl oleate, linoleate, and linolenate; some of the kinetic features of the nitrogen dioxide-initiated autoxidation of these unsaturated fatty acids have been studied.     

DDE residues and eggshell changes in Alaskan falcons and hawks

Eggshell thickness after exposure to DDT was reduced by 21.7 percent in Alaskan tundra peregrines, by 16.8 percent in taiga peregrines, by 7.5 percent in Aleutian peregrines, by 3.3 percent in rough-legged hawks, and not at all in gyrfalcons. Tundra peregrine eggs contain an average of 889 parts of DDE per million (lipid basis); taiga peregrine eggs contain 673 parts per million; Aleutian peregrine eggs contain 167 parts per million; rough-legged hawk eggs contain 22.5 parts per million; and gyrfalcon eggs contain 3.88 parts per million. These changes in eggshell thickness and the pesticide residues reflect different degrees of exposure to contamination. There is a highly significant negative correlation between shell thickness and DDE content in peregrine eggs. Tundra and taiga peregrines have fledged progressively fewer young each year since 1966.     

Pyrolysis-hydrogen flame ionization detection of organic carbon in a lunar sample

The lunar samples were analyzed for total organic carbon content by pyrolysis at 850 degrees C and subsequent detection of the resulting volatilized organic compounds in a hydrogen flame ionization detector. The organic content ranged from 10 to 126 parts per million, depending primarily upon the handling in the sample processing. No correlation of organic content with rock type has been shown. The small quantities of organic matter are primarily contamination, and the indigenous organic content is estimated to be less than 10 parts per million.     

Ozone Formation in Air Exposed to Cobalt-60 Gamma Radiation

The amount of ozone formed in air exposed to a 4000-curie cobalt-60 radiation source was determined. In closed glass containers exposed to about I Mrad of gamma radiation, ozone concentrations up to 18 parts per million (by volume) were recorded. In air flowing through a glass structure placed near the source, ozone contents up to 0.1 parts per million were observed. It is suggested that ozone formation might be a factor in the reported germicidal effects of ionizing radiations and that damage to plant tissues, ascribed to radiation, might have resulted from exposure to ozone. The possible health hazards from the ozone produced during irradiation should not be overlooked.     

Trace elements and accessory minerals in lunar samples

Halogen contents similar to those in meteorites are reported in Apollo 11 samples. Concentrations of 0.6 to 13 parts mercury, 0.2 to 0.8 part uranium, 1 to 17 parts lithium, and 1 to 800 parts osmium per million and 0.5 to 1 percent chromium oxide by weight have been measured. In contrast to meteorites and terrestrial rocks a large mercury release below 110 degrees C is observed. Some implications of these results are presented. Fluorapatite, quartz, tridymite, fayalite, and iron-rich, manganese-poor pyroxmangite, previously unreported, have been identified. The small amount of fluorapatite found does not account for the fluorine contents.     

Effects of trace gases and water vapor on the diffusion coefficient of polonium-218

The two-filter method described by Thomas and LeClare was used to investigate the effects of trace concentrations of nitric oxide and nitrogen dioxide in dry nitrogen on the diffusion coefficient of radium A (polonium-218). Charged radium A was neutralized in 10 parts per million (ppm) nitrogen dioxide in dry nitrogen, in 8.3 ppm nitric oxide in dry 92 percent nitrogen and 8 percent oxygen, and in nitrogen with 20 and 80 percent relative humidity. No neutralization was seen in dry nitrogen, dry oxygen, dry air, or 10 ppm nitric oxide in dry nitrogen. The diffusion coefficient of the neutral radium A species was found to be 0.079 square centimeters per second, regardless of the relative humidity of the nitrogen gas atmosphere. Lower values were observed for charged species.     

Ethyl mercury p-toluene sulfonanilide: lethal and reproductive effects on pheasants

Ethyl mercury p-toluene sulfonanilide (active ingredient of Ceresan M) at a dietary concentration of 30 parts per million (12.5 parts of mercury per million) was lethal to adult ring-necked pheasants. Egg production and survival of third-week embryos were sharply reduced when breeders were maintained on feed containing 10 parts of this compound per million (4.2 parts of mercury per million).     

不同氮浓度对茴香植株生长发育、精油含量和组分的影响

 【目的】揭示氮浓度对植物生长发育和次生代谢产物——精油累积的影响特性及其内在关系。【方法】采用水培方法,以日本园试配方中氮含量为标准1N,设计1/8N、1/4N、1/2N、1N和2N处理,研究不同氮浓度对茴香生长发育、精油含量和组分的影响。【结果】随着氮处理浓度的升高,茴香株高、分枝数、花序数、节数、地上部鲜重、全株鲜重、全株干重和单株精油产量等指标均表现为先不断增高,然后降低的规律,并且最高值均为1N处理;随着氮浓度的增加,茴香全氮含量、蛋白氮含量和色素含量呈不断增高趋势,全碳含量、可溶性糖、C/N比、精油含量呈不断降低的趋势;相关分析表明,全氮含量与蛋白氮含量极显著正相关;全碳含量、可溶性糖含量和碳氮比彼此呈极显著正相关;全氮含量和蛋白氮含量与全碳含量、可溶性糖含量和碳氮比彼此呈极显著负相关;精油含量与全碳含量、可溶性糖含量相关达到极显著正相关水平;单株精油产量分别与全氮含量、蛋白氮含量呈显著和极显著正相关;精油共鉴定出23种成分,不同氮浓度处理的茴香精油成分种类没有差别,但其成分相对含量差异达显著或极显著水平;精油第一主要成分反式-茴香脑含量为63.89%-79.28%,第二主要成分柠檬烯含量为5.65%-18.28%,第三主要成分莳萝芹菜脑相对含量2.26%-12.61%。【结论】不同氮浓度不但影响茴香的生长发育,还影响茴香次生代谢产物精油的含量、产量和成分组成比例;适宜的氮浓度（1N）可以实现茴香初生代谢产物累积（生长发育）与次生代谢产物累积（精油产量）均高的结果。     

Iodine-129/xenon-129 age of magnetite from the orgueil meteorite

Magnetite from the Orgueil C1 chondrite is only 2.0 +/- 2.4 million years older by the iodine-xenon method than the next oldest meteorite, the Karoonda C4 chondrite. This age ties the primitive C1 chondrites to the extensive iodine-xenon chronology of normal chrondrites. If Karoonda and Orgueil magnetite formed from similar material, then the age difference is an upper limit to the formation time of these meteorites-and by customary extension, the solar system. Condensation, chondrule formation, accretion, and metamorphism of the Karoonda parent body all seem to have been completed within a few million years.     

钼氮互作对烤烟总氮、烟碱及石油醚提取物含量的影响

研究了钼氮互作对不同部位烤烟烟叶总氮、烟碱和石油醚提取物的影响。结果表明:施用氮肥和钼肥均能够增强烟株氮代谢,其中施氮能够使总氮含量和石油醚提取物含量明显增加,且各部位烟叶石油醚提取物随施氮量的增加而增加。另外,在同等施氮条件下,施钼可以促进石油醚提取物含量的增加。钼氮配合施用对烤烟总氮含量的提高存在协同效应,但在同等施氮水平下,钼肥用量对烤烟总氮、烟碱和石油醚提取物含量的影响规律不尽相同。     

Lead isotopic ages of chondrules and calcium-aluminum-rich inclusions

The lead-lead isochron age of chondrules in the CR chondrite Acfer 059 is 4564.7 +/- 0.6 million years ago (Ma), whereas the lead isotopic age of calcium-aluminum-rich inclusions (CAIs) in the CV chondrite Efremovka is 4567.2 +/- 0.6 Ma. This gives an interval of 2.5 +/- 1.2 million years (My) between formation of the CV CAIs and the CR chondrules and indicates that CAI- and chondrule-forming events lasted for at least 1.3 My. This time interval is consistent with a 2- to 3-My age difference between CR CAIs and chondrules inferred from the differences in their initial 26Al/27Al ratios and supports the chronological significance of the 26Al-26Mg systematics.     

Silica in alkaline brines

Analysis of sodium carbonate-bicarbonate brines from closed basins in volcanic terranes of Oregon and Kenya reveals silica contents of up to 2700 parts per million at pH's higher than 10. These high concentrations of SiO(2) can be attributed to reaction of waters with silicates, and subsequent evaporative concentration accompanied by a rise in pH. Supersaturation with respect to amorphous silica may occur and persist for brines that are out of contact with silicate muds and undersaturated with respect to trona; correlation of SiO(2) with concentration of Na and total CO(2) support this interpretation. Addition of more-dilute waters to alkaline brines may lower the pH and cause inorganic precipitation of substantial amounts of silica.     

Organogenic elements and compounds in surface samples from the sea of tranquillity

Organogenic elements, mainly carbon, nitrogen, phosphorus, and sulfur are present in the particulate material and in a breccia rock from Tranquillity Base in amounts ranging from 5 to 4200 parts per million. The major compounds of carbon released by heating are carbon monoxide and carbon dioxide; the former predominates. Small amounts of other compounds of carbon have also been observed. Sulfur can be released as hydrogen sulfide by treatment with acid. The carbon isotopic delta(13L)C values are definitely nonterrestrial (+ 13 to + 18.5 per mil).