6,073 research outputs found
Conversion and Extraction of Insoluble Organic Materials in Meteorites
We endeavor to develop and implement methods in our laboratory to convert and extract insoluble organic materials (IOM) from low car-bon bearing meteorites (such as ordinary chondrites) and Precambrian terrestrial rocks for the purpose of determining IOM structure and prebiotic chemistries preserved in these types of samples. The general scheme of converting and extracting IOM in samples is summarized in Figure 1. First, powdered samples are solvent extracted in a micro-Soxhlet apparatus multiple times using solvents ranging from non-polar to polar (hexane - non-polar, dichloromethane - non-polar to polar, methanol - polar protic, and acetonitrile - polar aprotic). Second, solid residue from solvent extractions is processed using strong acids, hydrochloric and hydrofluoric, to dissolve minerals and isolate IOM. Third, the isolated IOM is subjected to both thermal (pyrolysis) and chemical (oxidation) degradation to release compounds from the macromolecular material. Finally, products from oxidation and pyrolysis are analyzed by gas chromatography - mass spectrometry (GCMS). We are working toward an integrated method and analysis scheme that will allow us to determine prebiotic chemistries in ordinary chondrites and Precambrian terrestrial rocks. Powerful techniques that we are including are stepwise, flash, and gradual pyrolysis and ruthenium tetroxide oxidation. More details of the integrated scheme will be presented
Colour Relations in Form
The orthodox monadic determination thesis holds that we represent colour relations by virtue of representing colours. Against this orthodoxy, I argue that it is possible to represent colour relations without representing any colours. I present a model of iconic perceptual content that allows for such primitive relational colour representation, and provide four empirical arguments in its support. I close by surveying alternative views of the relationship between monadic and relational colour representation
Two Distinct Secondary Carbonate Species in OC Meteorites from Antarctica are Possible Analogs for Mars Carbonates
Meteorites falling in Antarctica are captured in ice and stored until the glacial flow transports them to the surface where they can be collected. Prior to collection, they are altered during interactions between the rock, the cryosphere, and the hydrosphere. The purpose of this study is to characterize the stable isotope values of terrestrial, secondary carbonate minerals from Ordinary Chondrite (OC) meteorites collected in Antarctica. This facilitates better understanding of terrestrial weathering in martian meteorites as well as mechanisms for weathering in cold, arid environments as an analog to Mars. OC samples were selected for analysis based upon size and collection proximity to known martian meteorites. They were also selected based on petrologic type (3+) such that they were likely to be carbonate-free before falling to Earth
Experiences In Analysis And Monitoring Compressor Performance.
LecturePg. 3-10Evaluations of life cycle costs in typical turbomachinery installations have shown that for reliable machines, energy costs normally far outweigh purchase, installation, and maintenance costs. Experience has shown that flexibility in compressor system capacity can often be extremely valuable because many manufacturing plants are limited by compressor capacity. These factors have Jed to increased awareness of the values of efficiency, capacity flexibility, and performance analysis and monitoring, in addition to the traditional values for reliability. Typical compressor system life cycle costs estimates are discussed along with the value and benefits from the use of computerized performance analysis and monitoring techniques. Several typical examples of the application of performance analysis and monitoring technology are shown and the resulting benefits are presented
Resist or Comply:The Power Dynamics of Organizational Routines during Mergers
The role of power and agency in the development of organizational routines is under-theorized. In this paper, we draw on an in-depth qualitative case study of a merger between two academic institutions, a college of art and a university, and examine the diverging responses of two organizational routines (admissions and budgeting) during the course of the merger to understand how power dynamics contribute to resistance/compliance of routines. Our findings suggest that the differences in routinesâ responses to a merger initiative can be explained by applying Bourdieu's theory of practice and by employing the concepts of field and symbolic capital to unpack power relations in the context of organizational routines, and to disclose why some routine participants can exercise their agency while others cannot. We find that (a) the field within which a routine operates and (b) the actorsâ symbolic capital and position-taking during change implementation shape routinesâ responses to organizational change initiatives
Properties of a monolithic sapphire parametric transducer: prospects of measuring the standard quantum limit
To measure the standard quantum limit (SQL) a high quality transducer must be
coupled to a high quality mechanical system. Due to its monolithic nature, the
monolithic sapphire transducer (MST) has high quality factors for both types of
resonances. Single loop suspension is shown to yield a mechanical quality
factor of 6.10^8 at 4 K. From standard analysis we show the MST has the
potential to measure noise fluctuations of the mechanical oscillator at the
SQL. also, we point out a new way to determine if the transducer back action is
quantum limited. We show that if the fluctuations are at the quantum limit,
then the amplitude of the oscillation will be amplified by the ratio of the
ringdown time to the measurement time, which is an inherently easier
measurement.Comment: One PD
ELF3 controls thermoresponsive growth in Arabidopsis
Plant development is highly responsive to ambient temperature, and this trait has been linked to the ability of plants to adapt to climate change [1]. The mechanisms by which natural populations modulate their thermoresponsiveness are not known [2]. To address this, we surveyed Arabidopsis accessions for variation in thermal responsiveness of elongation growth and mapped the corresponding loci. We find that the transcriptional regulator EARLY FLOWERING3 (ELF3) controls elongation growth in response to temperature. Through a combination of modeling and experiments, we show that high temperature relieves the gating of growth at night, highlighting the importance of temperature-dependent repressors of growth. ELF3 gating of transcriptional targets responds rapidly and reversibly to changes in temperature. We show that the binding of ELF3 to target promoters is temperature dependent, suggesting a mechanism where temperature directly controls ELF3 activity
Hydrostatic low-range pressure applications of the ParisâEdinburgh cell utilizing polymer gaskets for diffuse X-ray scattering measurements
The use of a polymeric (Torlon or polyamideâimide) gasket material in a ParisâEdinburgh pressure cell for in situ high-pressure X-ray scattering measurements is demonstrated. The quality of the data obtained in this way is suitable for Bragg and pair distribution function analysis
Who am I? Autobiographical retrieval improves access to self-concepts
It is considered that an individual's current self-concept plays a crucial role in guiding the retrieval of autobiographical memory. Using a novel fluency paradigm, the present research examined whether or not the reverse is also true, that is, does memory retrieval influence the description of the conceptual self? Specifically, this study examined the effect of prior autobiographical reverie on the subsequent retrieval of stored self-concepts. Participants wrote a description of a personally relevant memory or a control topic (of no relevance to the self), following which they had 60 seconds to generate as many self-defining statements as possible, each beginning with I am. Participants engaging in autobiographical retrieval generated significantly more statements than those in the control condition, suggesting that autobiographical retrieval increased access to self-concepts. Type of statement also varied according to group. Participants in the autobiographical memory condition were more likely to conceptualise themselves in relation to their psychological traits, and this was replicated in a second experiment conducted online. Findings support the idea that self and episodic memory are highly related constructs, and are discussed in relation to implications for individuals with autobiographical memory deficits
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