873 resultados para multi-component and multi-site adsorption


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A new technique for the precise and accurate determination of Ge stable isotope compositions has been developed and applied to silicate rocks and biogenic opal. The analyses were performed using a continuous flow hydride generation system coupled to a MC-ICP-MS. Samples have been purified through anion- and cation-exchange resins to separate Ge from matrix elements and eliminate potential isobaric interferences. Variations of 74Ge/70Ge ratios are expressed as d74Ge values relative to our internal standard and the long-term external reproducibility of the data is better than 0.2? for sample size as low as 15 ng of Ge. Data are presented for igneous and sedimentary rocks, and the overall variation is 2.4? in d74Ge, representing 12 times the uncertainty of the measurements and demonstrating that the terrestrial isotopic composition of Ge is not unique. Co-variations of 74Ge/70Ge, 73Ge/70Ge and 72Ge/70Ge ratios follow a mass-dependent behaviour and imply natural isotopic fractionation of Ge by physicochemical processes. The range of d74Ge in igneous rocks is only 0.25? without systematic differences among continental crust, oceanic crust or mantle material. On this basis, a Bulk Silicate Earth reservoir with a d74Ge of 1.3+/-0.2? can be defined. In contrast, modern biogenic opal such as marine sponges and authigenic glauconite displayed higher d74Ge values between 2.0? and 3.0?. This suggests that biogenic opal may be significantly enriched in light isotopes with respect to seawater and places a lower bound on the d74Ge of the seawater to +3.0?.This suggests that seawater is isotopically heavy relative to Bulk Silicate Earth and that biogenic opal may be significantly fractionated with respect to seawater. Deep-sea sediments are within the range of the Bulk Silicate Earth while Mesozoic deep-sea cherts (opal and quartz) have d74Ge values ranging from 0.7? to 2.0?. The variable values of the cherts cannot be explained by binary mixing between a biogenic component and a detrital component and are suggestive of enrichment in the light isotope of diagenetic quartz. Further work is now required to determine Ge isotope fractionation by siliceous organisms and to investigate the effect of diagenetic processes during chert lithification.

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Whole-core measurements of Wet Bulk Density (WBD), compressional (P)-wave velocity (Vp), and Magnetic Susceptibility were measured at a sampling interval of 1 or 2 centimetres (cm) throughout the AND-2A drill core for initial core characterisation and on-site correlation with seismic modeling to predict target-reflector depth. Measurements were made using a GEOTEK (Multi-Sensor-Core-Logger MSCL). Density and velocity standards were measured together with core runs of 3-6 metres (m) (and occasionally up to 18 m) throughout the entire depth range to monitor data quality. Drift of the magnetic susceptibility sensor was also monitored and corrected where necessary. These physical properties show a large range of values, reflecting the different nature of the various lithologies including extremely high velocity and density values in individual clasts, and the effects of cementation on porosity. A downcore increase in WBD and Vp occurs in the upper 200 m, however, no systematic trend exists at greater depths although large fluctuations on a m-decimetre- (dm) scale occur. Magnetic susceptibility is generally low (<100 x 10-5 SI), however, four intervals of high (>600 x 10-5 SI) susceptibility occur at 560, 800, 980 and 1 080 mbsf, indicating a relatively greater contribution of volcanic-derived material to the core site in the lower half of the AND-2A core.

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Thesis (Ph.D.)--University of Washington, 2016-06

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This article reports a longitudinal study that examined mergers between three large multi-site public-sector organizations. Both qualitative and quantitative methods of analysis are used to examine the effect of leadership and change management strategies on acceptance of cultural change by individuals. Findings indicate that in many cases the change that occurs as a result of a merger is imposed on the leaders themselves, and it is often the pace of change that inhibits the successful re-engineering of the culture. In this respect, the success or otherwise of any merger hinges on individual perceptions about the manner in which the process is handled and the direction in which the culture is moved. Communication and a transparent change process are important, as this will often determine not only how a leader will be regarded, but who will be regarded as a leader. Leaders need to be competent and trained in the process of transforming organizations to ensure that individuals within the organization accept the changes prompted by a merger.

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Quantitatively predicting mass transport rates for chemical mixtures in porous materials is important in applications of materials such as adsorbents, membranes, and catalysts. Because directly assessing mixture transport experimentally is challenging, theoretical models that can predict mixture diffusion coefficients using Only single-component information would have many uses. One such model was proposed by Skoulidas, Sholl, and Krishna (Langmuir, 2003, 19, 7977), and applications of this model to a variety of chemical mixtures in nanoporous materials have yielded promising results. In this paper, the accuracy of this model for predicting mixture diffusion coefficients in materials that exhibit a heterogeneous distribution of local binding energies is examined. To examine this issue, single-component and binary mixture diffusion coefficients are computed using kinetic Monte Carlo for a two-dimensional lattice model over a wide range of lattice occupancies and compositions. The approach suggested by Skoulidas, Sholl, and Krishna is found to be accurate in situations where the spatial distribution of binding site energies is relatively homogeneous, but is considerably less accurate for strongly heterogeneous energy distributions.

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This thesis contributes to the paucity of marketing research into the area of internal marketing. Drawing from knowledge developed in a diverse range of marketing and management literatures, the domaill of internal marketing is clarified Gild a new concept, internal market orientation is developed. A new instrument, measuring the internal market orientation, is developed and subjected to standard scale development procedures. Six dimensions of the construct are confirmed; collegial interaction, group interaction, jorlllal interaction, external envirollment, wage flexibility and job flexibility. A sample of 766 UK retail store managers are surveyed to identify levels of internal market orientation and external market orientation in large UK multi-product, multi-site retailers and the structural relationships between internal market orientation, extemal market orientation alld company performance are examined. The external market orientation construct is applied to the local retail market and established measurement instruments adapted to this pwpose. Three measures of performance are employed ill this study. The structural relationships between the six dimensions of internal market orientation and the three dimensions of external market orientation are examined employing structural equations methodology, using LISREL 8.3. alld the impact of internal market orientation Oil external market orientation and company performance is measured. The study finds no direct link between internal market orientation and financial performance but does identify the moderated role of internal market orientation on financial performance. Significant relationships between three of the six dimensions of internal market orientation and the three dimensions of external market orientation are identified and the impact of internal market orientation on the retention of employees and their behaviour is also identified. The research findings contribute to marketing theory by providing empirical evidence to support the long held assumption that internal marketing has an impact on marketing success and offers an explanation of the mechanism by which this influence operates. For marketing practitioners, the research findings offer additional information on which services marketing strategies may be formulated.

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This multi-site, multi-ethnic/cultural study examined the effects of variation between ethnic/cultural groups and the effects of institutional variation within ethnic/cultural groups on identity formation. The participants were 892 late adolescent college students from six sites in 5 countries (Brazil, China, Costa Rica, US, and Sweden) representing different linguistic and ethnic/cultural traditions living in the context of varied social conditions. As hypothesized, there were significant differences in the proportion of identity statuses between sites in the Personal domain, $\chi\sp2$(20, N = 858) = 164.78, $p<.001,$ the Interpersonal domain, $\chi\sp2$(20, N = 858) = 145.69, $p<.001,$ and the World View domain, $\chi\sp2$(20, N = 858) = 120.89, $p<.001,$ but the distribution of the differences was more complex than expected. In addition, there were significant differences in Identity Satisfaction among sites, F(15, 2325) = 12.65, $p<.001.$ Further univariate analyses revealed that differences among sites were found on Identity Satisfaction in the personal, interpersonal and world view domain. The direction of the differences, however, were more complex than hypothesized.^ The second hypothesis was confirmed but only with the world view identity status and not for each of the six sites. Stepwise discriminant analyses showed that Identity status in the world view domain was predicted by Institutional Support in Nebraska, gender and Institutional Change in Brazil, and Institutional Access in China. Lastly and as hypothesized, some Institutional Attributes significantly predicted Overall Identity Satisfaction in all sites as revealed by multivariate regression analyses, except in Sweden, F (5, 79) =.660, p =.65. These findings extend the literature on identity formation not only by having investigated how culture influences the process of identity formation with samples representing different ethnic/cultural and linguistically different populations but also by empirically testing the role that social processes play in identity formation at the cross-cultural level. ^

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The management of residential landscapes occurs within a complex socio-ecological system linking household decision-making with ecological properties, multi-scalar human drivers, and the legacy effects of past management. Conventional wisdom suggests that resource-intensive turf grass yards are the most common landscaping outcome, resulting in a presumed homogeneous set of residential landscaping practices throughout North America. We examine this homogenization thesis through an interview-based, cross-site study of residential landscape management in Boston, Phoenix, and Miami. Counter to the homogeneity thesis, we find that yard management practices often exhibit heterogeneity, for example, in groundcover choice or use of chemical inputs. The degree of heterogeneity in management practices varies according to the scale of analysis, and is the outcome of a range of constraints and opportunities to which households respond differently depending on their existing yard and landscaping preferences. This study highlights the importance of multi-scalar and cross-site analyses of decision-making in socio-ecological systems, and presents opportunities for longitudinal and cross-site research to examine the extent to which homogeneity is actually present in the management of residential landscapes over time and in diverse places.

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This multi-site, multi-ethnic/cultural study examined the effects of variation between ethnic/cultural groups and the effects of institutional variation within ethnic/cultural groups on identity formation. The participants were 892 late adolescent college students from six sites in 5 countries (Brazil, China, Costa Rica, US, and Sweden) representing different linguistic and ethnic/cultural traditions living in the context of varied social conditions. As hypothesized, there were significant differences in the proportion of identity statuses between sites in the Personal domain, X2(20, N=858)= 164.78, p2(20, N=858)= 145.69, p2(20, N=858)= 120.89, p

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A collection of versatile best practices for promoting literacy development by utilizing local community connections in school and public libraries. This book provides a fresh approach to learning as well as guidelines for creating dynamic and relevant library programs for children, teens, and families. Organized thematically, each chapter includes relevant topical research and three to eight community-focused approaches. Programs range from small, single-library initiatives in rural communities to multi-site, cross-border initiatives. This resource includes collaborative and locally inspired programs, many of which can be scaled to the budget of any library, school, or community organization.

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Cloud computing enables independent end users and applications to share data and pooled resources, possibly located in geographically distributed Data Centers, in a fully transparent way. This need is particularly felt by scientific applications to exploit distributed resources in efficient and scalable way for the processing of big amount of data. This paper proposes an open so- lution to deploy a Platform as a service (PaaS) over a set of multi- site data centers by applying open source virtualization tools to facilitate operation among virtual machines while optimizing the usage of distributed resources. An experimental testbed is set up in Openstack environment to obtain evaluations with different types of TCP sample connections to demonstrate the functionality of the proposed solution and to obtain throughput measurements in relation to relevant design parameters.

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We present new d13C measurements of atmospheric CO2 covering the last glacial/interglacial cycle, complementing previous records covering Terminations I and II. Most prominent in the new record is a significant depletion in d13C(atm) of 0.5 permil occurring during marine isotope stage (MIS) 4, followed by an enrichment of the same magnitude at the beginning of MIS 3. Such a significant excursion in the record is otherwise only observed at glacial terminations, suggesting that similar processes were at play, such as changing sea surface temperatures, changes in marine biological export in the Southern Ocean (SO) due to variations in aeolian iron fluxes, changes in the Atlantic meridional overturning circulation, upwelling of deep water in the SO, and long-term trends in terrestrial carbon storage. Based on previous modeling studies, we propose constraints on some of these processes during specific time intervals. The decrease in d13C(atm) at the end of MIS 4 starting approximately 64 kyr B.P. was accompanied by increasing [CO2]. This period is also marked by a decrease in aeolian iron flux to the SO, followed by an increase in SO upwelling during Heinrich event 6, indicating that it is likely that a large amount of d13C-depleted carbon was transferred to the deep oceans previously, i.e., at the onset of MIS 4. Apart from the upwelling event at the end of MIS 4 (and potentially smaller events during Heinrich events in MIS 3), upwelling of deep water in the SO remained reduced until the last glacial termination, whereupon a second pulse of isotopically light carbon was released into the atmosphere.

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Living microorganisms inhabit every environment of the biosphere but only in the last decades their importance governing biochemical cycles in deep sediments has been widely recognized. Most investigations have been accomplished in the marine realm whereas there is a clear paucity of comparable studies in lacustrine sediments. One of the main challenges is to define geomicrobiological proxies that can be used to identify different microbial signals in the sediments. Laguna Potrok Aike, a maar lake located in Southeastern Patagonia, has an annually not stratifying cold water column with temperatures ranging between 4 and 10 °C, and most probably an anoxic water/sediment interface. These unusual features make it a peculiar and interesting site for geomicrobiological studies. Living microbial activity within the sediments was inspected by the first time in a sedimentary core retrieved during an ICDP-sponsored drilling operation. The main goals to study this cold subsaline environment were to characterize the living microbial consortium; to detect early diagenetic signals triggered by active microbes; and to investigate plausible links between climate and microbial populations. Results from a meter long gravity core suggest that microbial activity in lacustrine sediments can be sustained deeper than previously thought due to their adaptation to both changing temperature and oxygen availability. A multi-proxy study of the same core allowed defining past water column conditions and further microbial reworking of the organic fraction within the sediments. Methane content shows a gradual increase with depth as a result of the fermentation of methylated substrates, first methanogenic pathway to take place in the shallow subsurface of freshwater and subsaline environments. Statistical analyses of DGGE microbial diversity profiles indicate four clusters for Bacteria reflecting layered communities linked to the oxidant type whereas three clusters characterize Archaea communities that can be linked to both denitrifiers and methanogens. Independent sedimentary and biological proxies suggest that organic matter production and/or preservation have been lower during the Medieval Climate Anomaly (MCA) coinciding with a low microbial colonization of the sediments. Conversely, a reversed trend with higher organic matter content and substantial microbial activity characterizes the sediments deposited during the Little Ice Age (LIA). Thus, the initial sediments deposited during distinctive time intervals under contrasting environmental conditions have to be taken into account to understand their impact on the development of microbial communities throughout the sediments and their further imprint on early diagenetic signals.

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Background: There is growing evidence that individual EEG differences may aid in classifying patients with major depressive disorder (MDD) and also help predict clinical response to antidepressant treatment. This study aims to compare the effectiveness of EEG frequency band power, alpha asymmetry and prefrontal theta cordance towards escitalopram response prediction and MDD diagnosis, in a multi-site initiative. Methods: Resting EEG (eyes open and closed) was recorded from 64 electrodes in 44 depressed patients and 20 healthy controls at baseline, 2 weeks post-treatment and 8 weeks post-treatment. Clinical response was measured as change from baseline MADRS of 50% or more. EEG measures were analyzed (1) at baseline (2) at 2 weeks post-treatment and (3) as an ‘‘early change” variable defined as change in EEG from baseline to 2 weeks post-treatment. Results: At baseline, responders exhibited greater absolute alpha power in the left hemisphere versus the right while non-responders showed the opposite. Responders further exhibited a cortical asymmetry of greater right relative to left activity in parietal areas. Groups also differed in baseline relative delta power with responders showing greater power in the right hemisphere versus the left while non-responders showed the opposite. At 2 weeks post-treatment, responders exhibited greater absolute beta power in the left hemisphere relative to right and the opposite was noted for non-responders. The opposite pattern was noted for absolute and relative delta power at 2 weeks post-treatment. Responders exhibited early reduction in relative alpha power and early increments in relative theta power. Non-responders showed a significant early increase in prefrontal theta cordance. Absolute delta power helped distinguish MDD patients from healthy controls. Conclusions: Hemispheric asymmetries in the alpha and delta bands at pre-treatment baseline and at 2 weeks post-treatment have moderate to moderately strong predictive utility towards antidepressant treatment response. These findings have significant potential for improving clinical practice in psychiatry by eventually guiding clinical choice of treatments. This would greatly benefit patients awaiting relief from depressive symptoms as treatment optimization would help overcome problems associated with delayed recovery. Our results also indicate that resting EEG activity may have clinical utility in predicting MDD diagnosis.

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Thesis (Ph.D.)--University of Washington, 2016-08