Copper artifacts from prehistoric archeological sites in the dakotas

Thirteen archeological specimens were analyzed spectrographlically, and within defined limits they were determined to be native copper. Twelve of the specimens show close elemental homogeneity and are believed to be of Lake Superior ore; the origin of the other specimen is deviolus.     

4种竹叶超薄切片技术的研究

介绍4种竹叶超薄切片的制备方法,阐明它不同于木本植物超薄切片制备方法的机理.首次获得完好清晰的竹叶细胞超微结构的电镜照片.     

Free radicals in the stratosphere: a new observational technique

A new approach to in situ observations of trace reactive species in the stratosphere is described. A balloon-borne system, floating 40 kilometers above the earth's surface, successfully lowered and then retracted a cluster of instruments a distance of 12 kilometers on a filament of Kevlar. This instrument cluster is capable of detecting gas-phase free radicals at the part-per-trillion level. The suspended instrument array has excellent stability and has been used to measure atomic oxygen concentrations in the stratosphere.     

Lunar surface chemistry: a new imaging technique

Detailed chemical maps of the lunar surface have been constructed by applying a new weighted-filter imaging technique to Apollo 15 and Apollo 16 x-ray fluorescence data. The data quality improvement is amply demonstrated by (i) modes in the frequency distribution, representing highland and mare soil suites, which are not evident before data filtering and (ii) numerous examples of chemical variations which are correlated with small-scale (about 15 kilometer) lunar topographic features.     

Long base line interferometry: a new technique

The technique of using magnetic-tape recorders and atomic frequency standards to operate two widely separated radio telescopes as a phase-coherent interferometer when the stations have no radio-frequency connecting link has been successfully tested at the National Research Council of Canada's Algonquin Radio Observatory.     

Soil-water potential: direct measurement by a new technique

Current methods of measuring the potential of water in soil are inadequate. It is proposed to depress the reference free energy of water by a predetermined amount from the standard level of pure free water at atmospheric pressure by use of a solute. The specific free-energy difference of soil water from the depressed reference can be measured as a pressure.     

Computerized pattern recognition: a new technique for the analysis of chemical communication

Computerized pattern recognition techniques can be applied to the study of complex chemical communication systems. Analysis of high resolution gas chromatographic concentration patterns of the major volatile components of the scent marks of a South American primate, Saguinus fuscicollis, demonstrates that the concentration patterns can be used to predict the gender and subspecies of unknown donors.     

Laser-selective demagnetization: a new technique in paleomagnetism and rock magnetism

Laser-selective demagnetization (LSD) enables the determination of the magnetic moment associated with individual mineral grains in thin sections of rock. Small volumes can be demagnetize with laser pulses directed through the optics of a microscope, permitting resolution of remanence components in individual mineral grains. LSD of mafic granulite samples revealed two paleomagnetic directional components of opposite polarity: one resided in coarse magnetite, the other in ilmenohematite-hemoilmenite exsolution intergrowths and fine magnetite indusions in clinopyroxene. These directions are consistent with those inferred from bulk demagnetization techniques, but LSD permits direct identification of the remanence carriers. The ability to discriminate magnetization components in different generations of a single mineral and to define intergrain magnetic moment distributions are significant advantages of LSD.     

Particle track identification: application of a new technique to apollo helmets

The Apollo helmets are being used to record the dose of heavy particles to which astronauts are exposed on space missions. An improved method for examining and identifying the etched tracks of heavy charged particles consists of replicating tracks and measuring the etching rate as a function of position along the track. Tracks have been observed in Apollo helmets that correspond to ionized atoms heavier than iron.     

Micro-optical sectioning tomography to obtain a high-resolution atlas of the mouse brain

The neuroanatomical architecture is considered to be the basis for understanding brain function and dysfunction. However, existing imaging tools have limitations for brainwide mapping of neural circuits at a mesoscale level. We developed a micro-optical sectioning tomography (MOST) system that can provide micrometer-scale tomography of a centimeter-sized whole mouse brain. Using MOST, we obtained a three-dimensional structural data set of a Golgi-stained whole mouse brain at the neurite level. The morphology and spatial locations of neurons and traces of neurites could be clearly distinguished. We found that neighboring Purkinje cells stick to each other.     

Determining the general circulation of the oceans: a preliminary discussion

The classical oceanographic problem of deducing the unknown constant in the dynamic method-the problem of the "level of no motion"-may be treated as a geophysical inverse problem. The unknown "barotropic" velocity may be chosen to satisfy an arbitrary number of conservation laws, subject to perfect geostrophic balance and with explicit use made of the relative errors in the observations. The solution obtained is one of minimum energy. A western North Atlantic region is used to demonstrate the power of the method.     

Spontaneous fission-neutron fission xenon: a new technique for dating geological events

A method for dating geological samples which uses fission product xenon in a manner similar to the use of radiogenic argon in the 40Ar-39Ar technique has been developed. The results of stepwise heating experiments for a zircon from the Ahaggar region in the Sahara are compared to the geochronology determined by the rubidiumstrontium, uranium-thorium-lead, and potassium-argon dating methods.     

Neuronal soma and whole neuroglia of rat brain: a new isolation technique

Minced rat brain softened by treatment with trypsin is disrupted by filtration through nylon and steel meshes to produce a suspension of free-floating cells and debris. The cells are separated and purified by centrifugation on discontinuous sucrose gradients. Preparations of neuronal perikarya, retaining stumps of processes, so obtained are 90 percent pure and yield 33.6 x 10(6) cells per brain (3 milligrams, dry weight). The glial cells, apparently intact with extensive branched processess, are about 70 percent pure by weight and are obtained in a yield of 6.6 x 10(6) cells per brain (2 milligrams dry weight). The neurons are smaller and have less lipid than the glial cells.     

Neuronal soma and whole neuroglia of rat brain: a new isolation technique

In the report "Neuronal Soma and Whole Neuroglia of Rat Brain: A New Isolation Technique" by W. T. Norton and S. E. Podulso [167, 1144 (1970)], sentence 2, paragraph 3, column 1, p. 1144, should read: "The brains are trimmed of cerebellum and chopped fine (approximately 1 mm(3)) in an ice-cold medium consisting of 5 percent glucose, 5 percent fructose, and 1 percent bovine serum albumin (14) in 10 mM KH(2)PO(4)-NaOH buffer (pH 6.0)."     

新型凝胶酸奶加工工艺研究

提出了一种新型酸奶制品-凝胶型酸奶的加工工艺和技术条件，并就发酵终点酸度和氯化钙添加量对产品凝胶性的影响进行了试验分析，确定了最佳工艺参数。     

Hunting behavior of a marine mammal beneath the antarctic fast Ice

The hunting behavior of a marine mammal was studied beneath the Antarctic fast ice with an animal-borne video system and data recorder. Weddell seals stalked large Antarctic cod and the smaller subice fish Pagothenia borchgrevinki, often with the under-ice surface for backlighting, which implies that vision is important for hunting. They approached to within centimeters of cod without startling the fish. Seals flushed P. borchgrevinki by blowing air into subice crevices or pursued them into the platelet ice. These observations highlight the broad range of insights that are possible with simultaneous recordings of video, audio, three-dimensional dive paths, and locomotor effort.