显微镜及其用法

本书系英文版,为Munoz氏1942年西班文版后之另一著作,与A.Charipper合著者,唯内容大同小异,仅略加增删,故可视为Munoz氏原书之增订本。全书共分十章,第一章显微镜之演进举凡透镜之发现,     

Spatial Relationship between Dwelling Crowding and Selected Causes of Morbidity in Sydney,Australia, 1994–97

The environment in which we live greatly influences our health. One particular factor that has been related to morbidity and mortality is dwelling crowding. A range of mechanisms have been proposed as links between dwelling crowding and disease, including increased exposures to allergens, respiratory irritants and infectious agents in crowded dwellings. While studies of dwelling crowding have been conducted in many locations around the world, this factor has received little attention in Australian health studies. We examine relationships between dwelling crowding and health in Sydney, using three case studies at the local government area (LGA) level within the Sydney Statistical Division. Dwelling and demographic data from the 1996 Australian census are used, along with four socio-economic indexes produced by the Australian Bureau of Statistics, and hospital inpatient data for the period 1 July 1994 to 30 June 1997 as the health indicator. Results suggest that dwelling crowding is a significant factor in certain diseases in Sydney. Asthma hospital separations are not correlated with dwelling crowding, although multiple linear regression analysis produces three models which include crowding and three of the socio-economic indexes as significant variables. Separations for bronchitis and emphysema, and all causes combined, are positively correlated with dwelling crowding. Dwelling crowding is strongly negatively correlated with all but one of the socio-economic indicators.     

Grouped regression analysis—A sedimentologic example

When sample data are divided into groups, and observations consist of the independent variable xand associated dependent variable y,a logical form of analysis is “grouped regression.” This statistical technique allows testing of the relationship between the two variables and assessment of how the relationship is affected by the grouping. A sedimentologic example illustrates the usefulness of such a technique in classifying environments of deposition based on the size of quartz grains and the quartz content.     

A metal particle from a Ca,Al-rich inclusion from the meteorite Allende,and the condensation of refractory siderophile elements

A small particle (ca. 10^?6 g) was magnetically separated from a Ca,Al-rich inclusion of the Allende meteorite. By using instrumental neutron activation analysis it was found that the elements Os, W, Re, Ir, Mo, Ru and Pt were enriched by a mean factor of about 7000 relative to Cl chondrites.A polished section of the grain showed that it consisted mainly of silicates, with a rounded particle of metal and sulfide (20 μm across) attached to it.Concentrations of up to 11% Pt were determined with the microprobe in the Ni-Fe center of the particle. Furthermore, Rh was for the first time measured in an Allende inclusion. It is enriched in about the same degree as Pt, Ir and W. The Ni-Fe center was surrounded by troilite. Mo was concentrated in the sulfide, while Os and Ru were inhomogeneously distributed over the metal + sulfide phases. The particle is interpreted as direct product of metal condensation of the solar nebula. The sulfide phase formed at lower temperatures and caused redistribution of the refractory siderophile elements. Condensation calculations for a metal alloy show that Fe and Ni are expected to be already present at higher temperatures than the condensation temperatures of pure Fe. Pt and Rh, having lower condensation temperatures than pure Fe should also be completely condensed above the condensation temperature of pure Fe. Kinetic considerations show that minimum times to grow this kind of particle should be of the order of 500 years at 10^?3 atm.     

A thermal model of the earth

A thermal model, consistent as far as possible with the parameterised earth model of Dziewonski et al. and with thermodynamic principles and relevant equations of state, is tabulated. This is made more secure by two recent developments, an experimental study of the FeS eutectic to 100 kbar by Usselman and a calculation by Bukowinski which reveals an electronic phase collapse of potassium in the 200–300 kbar range and explains the core heat source. Use is made of the Vashchenko-Zubarev formulation of the Grüneisen ratio, and Lindemann's melting law, both of which have been shown recently to have particular relevance at very high pressures. Values of electronic specific heat and the Grüneisen ratio, which contribute significantly to core properties are calculated from the electron equation of state of Zharkov and Kalinin.     

Theory of the piezomagnetic effect in titanomagnetite-bearing rocks

Summary The stress sensitivitiesS _x andS _R of susceptibility and remanence for titanomagnetite-bearing rocks are calculated in terms of magnetostriction constants ₁₀₀ and ₁₁₁ and anisotropy constantsK ₁,K ₂ of the magnetic minerals.S _x andS _R are represented by quite different algebraic expressions but happen to have comparable numerical values over the whole range of titanomagnetite compositions. Both increase strongly with titanium content. This leads to more optimistic calculations of tectonomagnetic effects than with the previously assumed stress sensitivity for pure magnetite.     

On the role of Brownian motion in the control of detrital remanent magnetization of sediments

Summary The field dependence of magnetic remanence in laboratory deposited sediments is re-examined in terms of the average orientation of small grains of magnetite subject to the combined effect of an aligning field and thermal agitation. The classical (Langevin) formula for paramagnetic susceptibility is generalized to describe an assembly of grains with magnetic moments having a uniform distribution of values between zero and an upper limit, yielding a simple analytical expression in excellent accord with the pioneering measurements of Johnson, Murphy and Torreson. Comparison of theory and observation shows that the grain moments are intermediate between the values expected for single domains and multidomains, confirming the existence of pseudo-single domain effects, as deduced from observations of thermoremanence.