Laboratory study of nitrate photolysis in Antarctic snow. II. Isotopic effects and wavelength dependence

AbstractIn recent years the wavelength, dependence of the polarization in a number of Mira variables, semi-regular variables and red supergiants has been measured with resolutions between 0.3 and 300 A over the range 3300 to 11000 A. Variations are seen across molecular absorption bands, especially TiO bands, and across atomic absorption and emission lines, especially the Balmer lines. In most cases one can ignore or it is possible to eliminate the effects due to interstellar polarization, so that one can study the polarization mechanisms operating in the stellar atmosphere and environment. The stars Omicron Ceti. (Mira), V CVn (semi-regular variable) and Mu Cephei (M2 la), in addition to other stars similar to them, will be discussed in some detail.Models to explain the observed polarization consider that the continuum flux is polarized either by electron, molecular and/or grain scattering or by temperature variations and/or geometrical asymmetries over the stellar photosphere. This polarized radiation is affected by atomic and molecular absorption and emission processes at various geometric depths in the stellar atmosphere and envelope. High resolution spectropolarimetry promises, therefore, to be a power-rul tool for studying stratification effects in these stars.

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Laboratory and in-situ analysis of comet dust

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100102122 ◽

1988 ◽

Vol 46 ◽

pp. 8-9

Author(s):

D.E. Brownlee ◽

A.L. Albee

Keyword(s):

Electron Microscopy ◽

Solar System ◽

Laboratory Study ◽

Isotopic Analysis ◽

Building Blocks ◽

Sem Analysis ◽

Early Solar System ◽

Cometary Material ◽

Comet Dust

Comets are primitive, kilometer-sized bodies that formed in the outer regions of the solar system. Composed of ice and dust, comets are generally believed to be relic building blocks of the outer solar system that have been preserved at cryogenic temperatures since the formation of the Sun and planets. The analysis of cometary material is particularly important because the properties of cometary material provide direct information on the processes and environments that formed and influenced solid matter both in the early solar system and in the interstellar environments that preceded it.The first direct analyses of proven comet dust were made during the Soviet and European spacecraft encounters with Comet Halley in 1986. These missions carried time-of-flight mass spectrometers that measured mass spectra of individual micron and smaller particles. The Halley measurements were semi-quantitative but they showed that comet dust is a complex fine-grained mixture of silicates and organic material. A full understanding of comet dust will require detailed morphological, mineralogical, elemental and isotopic analysis at the finest possible scale. Electron microscopy and related microbeam techniques will play key roles in the analysis. The present and future of electron microscopy of comet samples involves laboratory study of micrometeorites collected in the stratosphere, in-situ SEM analysis of particles collected at a comet and laboratory study of samples collected from a comet and returned to the Earth for detailed study.

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The effect of venting on pulpward pressure transmission and seating on crown cementation: a laboratory study

Journal of Oral Rehabilitation ◽

10.1046/j.1365-2842.2000.00612.x ◽

2000 ◽

Vol 27 (11) ◽

pp. 958-966 ◽

Cited By ~ 4

Author(s):

T. W. H. Yuen ◽

P. R. Wilson

Keyword(s):

Laboratory Study ◽

Pressure Transmission

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Solar urticaria. Clinical features and wavelength dependence

Archives of Dermatology ◽

10.1001/archderm.118.4.228 ◽

1982 ◽

Vol 118 (4) ◽

pp. 228-231 ◽

Cited By ~ 11

Author(s):

M. Ravits

Keyword(s):

Clinical Features ◽

Wavelength Dependence ◽

Solar Urticaria

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When Apologies for Injustice Matter

European Psychologist ◽

10.1027/1016-9040.13.4.239 ◽

2008 ◽

Vol 13 (4) ◽

pp. 239-247 ◽

Cited By ~ 26

Author(s):

David De Cremer ◽

Barbara C. Schouten

Keyword(s):

Laboratory Study ◽

Interaction Effect ◽

Interactive Effect ◽

Cross Sectional ◽

Fairness Perceptions ◽

Organizational Survey ◽

Experimental Laboratory

The present research examined the idea that the effectiveness of apologies on promoting fairness perceptions depends on how meaningful and sincere the apology is experienced. More precisely, it was predicted that apologies are more effective when they are communicated by an authority being respectful to others. A study using a cross-sectional organizational survey showed that an apology (relative to giving no apology) revealed higher fairness perceptions, but only so when the authority was respectful rather than disrespectful. In a subsequent experimental laboratory study the same interaction effect (as in Study 1) on fairness perceptions was found. In addition, a similar interaction effect also emerged on participants’ self-evaluations in terms of relational appreciation (i.e., feeling valued and likeable). Finally, these self-evaluations accounted (at least partly) for the interactive effect on fairness perceptions.

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