7,039 research outputs found

    The spectroscopic chemical and photophysical properties of Martian soils and their analogs

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    The program of research outlined should advance significantly the understanding of the spectral signal of montmorillonites in general and the variations produced in it by structural and surface ferric and ferrous iron and interlayer water as a function of several environmental conditions that are different between Earth and Mars. In addition, an extensive data base was collected providing spectral characterization of several features (iron, both surface and structural, OH-groups, both structural and from adsorbed water and O(-) centers) that are known, or thought to be, influential in directing the surface activity of these important materials. With this data base with which to assess the results of the Viking labeled release simulation studies, it should be possible to gain important insights into the mechanisms of surface reactivity for this important chemical reaction. The results to be gained from these studies will provide a significant body of ground base truth from which to assess: the presence of smectite clays on Mars; the mineralogical form in which the Martian iron is bound; establish upper limits on the present surface water content of Martian soils; perhaps provide insights on the Martian surface radiation history; and to make strong predictions about the nature of surface chemistry on Mars, if iron-bearing clays are a significant component of the surface mineralogical assemblage

    Kaolinite-catalyzed air oxidation of hydrazine: Consideration of several compositional, structural and energetic factors in surface activation

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    Clay minerals have been shown to have numerous, curious, energetic properties by virtue of ultra-violet light release which can be triggered by gentle environmental changes such as wetting and dewetting by a variety of liquids, unique among them water and hydrazine. Since both water and hydrazine play multiple key roles in the air-oxidation of hydrazine on kaolinite surfaces, this reaction would seem to have prime potential for studying interrelationships of energy storage, release and chemical reactivity of clay surfaces, capacities basic to either the Bernal or Cairns-Smith roles of minerals in the origin of life. Establishment of the capacity for stored electronic energy to significantly alter surface chemistry is important, regardless of the reaction chosen to demonstrate it. Hydrazine air oxidation is overawingly complex, given the possibilities for step-wise control and monitoring of parameters. In the light of recently extended characterization of the kaolinite and model sheet catalysts we used to study hydrazine oxidation and gamma-irradiated silica, previous studies of hydrazine air-oxidation on aluminosilicate surfaces have been reevaluated. Our former conclusion remains intact that, whereas trace structural and surface contaminants do play some role in the catalysis of oxidation, they are not the only, nor even the dominant, catalytic centers. Initial intermediates in the oxidation can now be proposed which are consistent with production via O(-)-centers as well as ferric iron centers. The greater than square dependence of the initial reaction rate on the weight of the clay is discussed in the light of these various mechanistic possibilities

    Distress in couples coping with cancer: A meta-analysis and critical review of role and gender effects

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    Research concerning distress in couples coping with cancer was integrated using meta-analysis and narrative critical appraisal. Individual levels of distress were determined more by gender than by the role of being the person with cancer versus that person's partner. That is, women reported consistently more distress than men regardless of their role (standardized mean difference = 0.31). The association between patient and partner distress within couples was only moderate (r = .29) but is sufficient to warrant further consideration of the notion that these couples react as an emotional system rather than as individuals. It is noteworthy that this association is not moderated by gender. With a general lack of comparison groups, the question of how much distress can be ascribed to the cancer experience cannot be answered decisively; elevations in distress are probably modest. We critically discuss these results, identify important unanswered questions, and indicate directions for future research. Attention needs to be directed toward factors other than cancer as direct influences of distress in these couples and to mediators and moderators of the cancer experience. (PsycINFO Database Record (c) 2008 APA, all rights reserved)

    Adolescents' and parents' views of Child and Adolescent Mental Health Services (CAMHS) in Ireland

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    Aim: To explore adolescents’ and parents’ experiences of CAMHS in relation to accessibility, approachability, and appropriateness. Methods: Using a descriptive qualitative design, a combination of focus group and single interviews were conducted with adolescents (n=15) and parents (n=32) from three mental health clinics. Data were transcribed verbatim and analysed using thematic analysis. Results: Accessing mental health services was a challenging experience due to knowledge deficit, lack of information and limited availability of specialist services. Participants desired more information, involvement in decision-making, single and shared consultations, flexible scheduling of appointments, continuity with clinicians, school support and parent support groups. Participants seem to be generally satisfied, however adolescents felt less involved in decision making than they would have liked. Frequent staff changes was problematic as it disrupted continuity of care and hindered the formation of a trusting relationship. Implications for practice: Parents and adolescents expressed similar views of the positive and negative aspects of mental health services. Their need for more information-sharing and involvement in decision-making underline the importance of collaborative practice. Clinician continuity contributed to trusting therapeutic relationships and was valued. These are key principles that with attention, could lead to quality service provision for adolescents and families

    A Tribute to Rosalie E. Wahl

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    Beowulf : Worda and Worca

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    This Project can be Upcycled where Facilities are Available: An Adventure Through Toronto's Food/Waste Scape

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    At the intersection of food, regulations, and subjective experiences is a new way of understanding the intersection of wasted food—a new category of edibility. This project investigates the reasons for, and impacts of, politically-motivated dumpster diving and food reclamation activism in Toronto, Canada. The research incorporates ethnographic participant-observation and interviews with politically-motivated dumpster divers in Toronto, as well as that city’s chapter of Food Not Bombs. The project primarily asks how so much quality food/waste is thrown away and becomes, at times, available to be recovered, reworked, and eaten. My research constitutes a living critique of the hybrid experience of food and waste where the divisions between the two categories are not found in locations (the grocery store or dumpster), but rather in the circulations of actions and meanings that dumpster divers themselves re-invest in discarded edible food products. My research objectives are: (1) to document the experience of dumpster divers in Toronto as connected to a broader movement of food/waste activism around the world; (2) to connect this activism to discussions of food safety and food regulations as structuring factors ensuring that edible food is frequently thrown away; (3) to contextualize contemporary food/waste activism within a history of gleaning, and in relation to enclosure acts that have left Canada with no legal protections for gleaners nor recognition of the mutually beneficial social relation between gleaners and farmers; (4) to explore dumpster divers’ work as part of the circulation of urban culture within media networks. Ultimately, I isolate alternative gift economies as central to dumpster divers’ critique of industrial food distribution within the commodity systems of global capitalism. This gifting relation proves to be, in part, a nostalgic view of an idealized past. Nonetheless, the gifting relation becomes an ideal linked to broader anarchist communities that allows divers to create communal subject identities that exist outside of market relations, made global through communication networks of independent and self-published media. By connecting globally, the small-scale, local actions of Food Not Bombs chapters around the world allow surprisingly few individuals to spread a politic with the potential to impact beyond their limited political circles. This project is theoretically situated at the junction of studies of material culture, food and food waste, and new social movements; I connect political experience in local communities to the circulation of food and waste through urban environments and media networks. For the dumpster diver, edibility is delinked from purchase price and is instead imbedded in systems of power and active resistance

    Multicolor optical polarimetry of reddened stars in the small Magellanic cloud

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    First results of an on-going program to determine the wavelength dependence of the interstellar optical polarization of reddened stars in the Small Magellanic Cloud (SMC) are presented. IUE observations of reddened stars in the SMC (Bouchet et al. 1985) generally show marked differences in the extinction law as compared to both the Galaxy and the Large Megallanic Cloud. The aim here is to determine the wavelength dependence of the optical linear polarization in the direction of several such stars in the SMC in order to further constrain the dust composition and size distribution in that galaxy

    Use of near infrared correlation spectroscopy for quantitation of surface iron, absorbed water and stored electronic energy in a suite of Mars soil analog materials

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    A number of questions concerning the surface mineralogy and the history of water on Mars remain unresolved using the Viking analyses and Earth-based telescopic data. Identification and quantitation of iron-bearing clays on Mars would elucidate these outstanding issues. Near infrared correlation analysis, a method typically applied to qualitative and quantitative analysis of individual constituents of multicomponent mixtures, is adapted here to selection of distinctive features of a small, highly homologous series of Fe/Ca-exchanged montmorillonites and several kalinites. Independently determined measures of surface iron, relative humidity and stored electronic energy were used as constituent data for linear regression of the constituent vs. reflectance data throughout the spectral region 0.68 to 2.5 micrometers. High correlations were found in appropriate regions for all three constituents, though that with stored energy is still considered tenuous. Quantitation was improved using 1st and 2nd derivative spectra. High resolution data over a broad spectral range would be required to quantitatively identify iron-bearing clays by remotely sensed reflectance

    Spectroscopic analyses of Fe and water in clays: A Martian surface weathering study

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    Martian surface morphology suggests the presence of liquid H2O on Mars in the past. Reflectance spectra of the Martian surface include features which correspond to the crystal field transitions of iron, as well as features supporting the presence of ice and minerals containing structural OH and surface water. Researchers initiated further spectroscopic studies of surface iron and water and structural OH in clays in order to determine what remotely obtained spectra can indicate about the presence of clays on Mars based on a clearer understanding of the factors influencing the spectral features. Current technology allows researchers to better correlate the low frequency fundamental stretching and bending vibrations of O-H bonds with the diagnostic near infrared overtone and combination bands used in mineral characterization and identification
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