Argon resonance line lamp for vacuum ultraviolet photochemistry

The use of rare gas resonance line lamps as sources of monochromatic radiation for photochemical studies is well known.(1-5) Argon is ideally suited for photoionization studies of the simpler hydrocarbons which have ionization potentials below 11.6 eV. It has resonance lines at 1048 Å (11.83 eV) and 1067 Å (11.62 eV), with no other emission lines between 1050 and 2000 Å when pressures less than 1 Torr are used

Terms of engagement: The collaborative representation of Alutiiq identity

Le livre et l’exposition Looking Both Ways: Heritage and Identity of the Alutiiq People (Regards croisés: patrimoine et identité du peuple alutiiq) présentent une perspective à la fois alutiiq et anthropologique d’une société autochtone d’Alaska. Ce projet, fondé sur un partenariat communautaire et mené par la Smithsonian Institution et le Musée alutiiq de Kodiak, est considéré sous plusieurs angles: identité culturelle et revitalisation de la région alutiiq, nouveau paradigme de l’anthropologie en collaboration et opposition des modèles essentialistes et constructivistes du changement culturel. On propose l’existence d’une «logique culturelle» alutiiq de liens ancestraux, de parenté, de lieu et d’un milieu riche qui agissent comme fondements de la permanence de l’identité à travers deux siècles de transformations culturelles. L’entente de collaboration dans le cadre de projets sur le patrimoine autochtone est présentée comme un engagement complexe mais indispensable à l’anthropologie contemporaine.The book and exhibition Looking Both Ways: Heritage and Identity of the Alutiiq People present both Alutiiq and anthropological perspectives on a complex Alaska Native ethnicity. This community-based project, produced by the Smithsonian Institution and Alutiiq Museum in Kodiak, is considered within several frames: cultural identity and revitalization in the Alutiiq region, the new paradigm of collaborative anthropology, and contrasting essentialist and constructivist models of cultural change. An Alutiiq “cultural logic” of connection to ancestors, kin, place and a provident natural environment is proposed as the basis for continuity of identity through two centuries of cultural transformation. Collaborative engagement in Indigenous heritage projects is discussed as a complex but indispensable commitment for contemporary anthropology

Evolution of miniaturisation in inquiline parasitic ants: Timing of male elimination in Plagiolepis pygmaea, the host of Plagiolepis xene

Inquiline ant species are workerless social parasites whose queens rely completely on the host worker force to raise their brood. A remarkable feature of inquiline ants is the small size of sexuals, which are of the same size as or smaller than host workers. It has been suggested that miniaturisation evolved by parasites to prevent host workers from discriminating between their own worker brood and the inquiline sexuals, so that male and female inquilines can develop under conditions where the host species does not produce its own sexuals. In line with the miniaturisation hypothesis, workers of the ant P. pygmaea cull all the male brood of their own species, whereas at the same time males of their inquiline parasite P. xene are reared to adulthood. Here, we tested whether P. pygmaea workers recognize and eliminate males of their own species when they reach the size of the larger workers. Contrary to the assumption that size is indeed the primary cue used by workers to discriminate male from worker brood, we found that males of P. pygmaea are culled between the small and medium larval stages, that is much before reaching the critical size of the largest worker larvae. Based on this finding, we propose an extension of the miniaturisation hypothesis with a first step whereby the parasitic P. xene males escape the caste and sex recognition system of the host during early development. The most likely mechanism is chemical mimicry of host worker larvae. Miniaturisation would have evolved later to prevent the host workers to secondarily use size as a recognition cue to eliminate P. xene males

Millimeter-Wave Imaging Radiometer (MIR) Data Processing and Development of Water Vapor Retrieval Algorithms

This document describes the final report of the Millimeter-wave Imaging Radiometer (MIR) Data Processing and Development of Water Vapor Retrieval Algorithms. Volumes of radiometric data have been collected using airborne MIR measurements during a series of field experiments since May 1992. Calibrated brightness temperature data in MIR channels are now available for studies of various hydrological parameters of the atmosphere and Earth's surface. Water vapor retrieval algorithms using multichannel MIR data input are developed for the profiling of atmospheric humidity. The retrieval algorithms are also extended to do three-dimensional mapping of moisture field using continuous observation provided by airborne sensor MIR or spaceborne sensor SSM/T-2. Validation studies for water vapor retrieval are carried out through the intercomparison of collocated and concurrent measurements using different instruments including lidars and radiosondes. The developed MIR water vapor retrieval algorithm is capable of humidity profiling under meteorological conditions ranging from clear column to moderately cloudy sky. Simulative water vapor retrieval studies using extended microwave channels near 183 and 557 GHz strong absorption lines indicate feasibility of humidity profiling to layers in the upper troposphere and improve the overall vertical resolution through the atmosphere

Millimeter-wave imaging radiometer data processing and development of water vapor retrieval algorithms

This document describes the current status of Millimeter-wave Imaging Radiometer (MIR) data processing and the technical development of the first version of a water vapor retrieval algorithm. The algorithm is being used by NASA/GSFC Microwave Sensors Branch, Laboratory for Hydrospheric Processes. It is capable of a three dimensional mapping of moisture fields using microwave data from airborne sensor of MIR and spaceborne instrument of Special Sensor Microwave/T-2 (SSM/T-2)

Millimeter-wave Imaging Radiometer (MIR) data processing and development of water vapor retrieval algorithms

This document describes the progress of the task of the Millimeter-wave Imaging Radiometer (MIR) data processing and the development of water vapor retrieval algorithms, for the second six-month performing period. Aircraft MIR data from two 1995 field experiments were collected and processed with a revised data processing software. Two revised versions of water vapor retrieval algorithm were developed, one for the execution of retrieval on a supercomputer platform, and one for using pressure as the vertical coordinate. Two implementations of incorporating products from other sensors into the water vapor retrieval system, one from the Special Sensor Microwave Imager (SSM/I), the other from the High-resolution Interferometer Sounder (HIS). Water vapor retrievals were performed for both airborne MIR data and spaceborne SSM/T-2 data, during field experiments of TOGA/COARE, CAMEX-1, and CAMEX-2. The climatology of water vapor during TOGA/COARE was examined by SSM/T-2 soundings and conventional rawinsonde

Electron-Impact Spectroscopy

A spectrometer has been devised for determining electronic energy levels of molecules by inelastic scattering of low-energy electrons. It permits the detection of optically forbidden electronic transitions as clearly as optically allowed ones in a routine manner. The spectrometer has been used to obtain excitation spectra for helium, argon, hydrogen and ethylene. For the first three of these substances, the spectra agree with previous experiments. For ethylene, in addition to optically allowed transitions, two forbidden ones occur at about 4-6 and 6-5eV. Variation of peak heights with incident electron beam energy suggest that the first corresponds to a triplet state but that the second does not