Effects of experimental conditions on the sorption of organic compounds to soils and sediments

Sorption is the basis for a number of techniques used to characterize solid particles. Because a number of techniques are based on sorptive interactions which are not fully understood, they are often plagued by experimental inconsistencies that are difficult to explain and frequently ignored. The purpose of this dissertation is to examine two techniques that are complicated by experimental inconsistencies--surface area measurements and the determination of distribution coefficients. The apparent surface area of illite was measured by adsorption of a cationin fluorescent dye, Pyronin-y, from aqueous solutions in which pH and ionic strength were systematically varied. Estimates were highly dependent on pH, while ionic strength effects depended on the composition and pH of the buffer solutions. A complete lack of sorption of the anionic dye, New Coccine, to illite was also observed. Results indicated that the interactions between illite and dyes were primarily electrostatic. Variations in experimental procedures frequently result in a wide range of distribution coefficients measured for a single compound. Distribution coefficients have been reported to vary inversely with the solid-to-solution ratio used to measure coefficients. One explanation attributes this effect to the production of microparticulates during batch equilibration and the subsequent inability to separate these particles from the aqueous phase. A mathematical model was developed which highlights the effect microparticulates can have on the measurement of distribution coefficients when different methods of analysis are used. Distribution coefficients measured using the counting of radiolabelled analytes will be underestimated and can vary significantly with sediment concentration. Distribution coefficients measured by fluorescence quenching will be overestimated and will only be slightly influenced by sediment concentration. These predictions were supported on a qualitative basis by distribution coefficients measured for the sorption of anthracene to sediment using radiolabelling and fluorescence quenching techniques. To further evaluate this theory, the effect of equilibration time, type of agitation, sediment concentration and separation efficiency on the production of microparticulates during a batch equilibration experiment were studied. Based on total organic carbon concentration and conductivity measurements for the aqueous phase, sediment concentration was found to be the only variable which significantly influenced the production of microparticulates

Data Service Provider Cost Estimation Tool

The Data Service Provider Cost Estimation Tool (CET) and Comparables Database (CDB) package provides to NASA s Earth Science Enterprise (ESE) the ability to estimate the full range of year-by-year lifecycle cost estimates for the implementation and operation of data service providers required by ESE to support its science and applications programs. The CET can make estimates dealing with staffing costs, supplies, facility costs, network services, hardware and maintenance, commercial off-the-shelf (COTS) software licenses, software development and sustaining engineering, and the changes in costs that result from changes in workload. Data Service Providers may be stand-alone or embedded in flight projects, field campaigns, research or applications projects, or other activities. The CET and CDB package employs a cost-estimation-by-analogy approach. It is based on a new, general data service provider reference model that provides a framework for construction of a database by describing existing data service providers that are analogs (or comparables) to planned, new ESE data service providers. The CET implements the staff effort and cost estimation algorithms that access the CDB and generates the lifecycle cost estimate for a new data services provider. This data creates a common basis for an ESE proposal evaluator for considering projected data service provider costs

Generating rural options for Weight: Healthy Kids and Communities: examining the rural family home nutrition and physical activity environment

Childhood health is a strong determinant of adult health, including overweight and obesity. Rural children and adults experience a greater obesity prevalence compared to children and adults living in more urban places. The goal of Generating Rural Options for Weight-Healthy Kids & Communities (GROW HKC) is to prevent childhood obesity and promote healthy weight among children and families living in rural places. GROW HKC focuses efforts in rural communities, schools, and families. The data presented here focus on the rural family home environment. PURPOSE: The purpose of this investigation was to examine the family home food and physical activity environment among rural families

Multiple Paths Forward: Diversifying Mathematics as a Strategy for College Success (Executive Summary)

This executive summary outlines key findings from a report on how colleges are creating math pathways that are aligned with students' programs of study

MicroRNA 146a (miR-146a) Is Over-Expressed during Prion Disease and Modulates the Innate Immune Response and the Microglial Activation State

Increasing evidence supports the involvement of microRNAs (miRNAs) in inflammatory and immune processes in prion neuropathogenesis. MiRNAs are small, non-coding RNA molecules which are emerging as key regulators of numerous cellular processes. We established miR-146a over-expression in prion-infected mouse brain tissues concurrent with the onset of prion deposition and appearance of activated microglia. Expression profiling of a variety of central nervous system derived cell-lines revealed that miR-146a is preferentially expressed in cells of microglial lineage. Prominent up-regulation of miR-146a was evident in the microglial cell lines BV-2 following TLR2 or TLR4 activation and also EOC 13.31 via TLR2 that reached a maximum 24–48 hours post-stimulation, concomitant with the return to basal levels of transcription of induced cytokines. Gain- and loss-of-function studies with miR-146a revealed a substantial deregulation of inflammatory response pathways in response to TLR2 stimulation. Significant transcriptional alterations in response to miR-146a perturbation included downstream mediators of the pro-inflammatory transcription factor, nuclear factor-kappa B (NF-κB) and the JAK-STAT signaling pathway. Microarray analysis also predicts a role for miR-146a regulation of morphological changes in microglial activation states as well as phagocytic mediators of the oxidative burst such as CYBA and NOS3. Based on our results, we propose a role for miR-146a as a potent modulator of microglial function by regulating the activation state during prion induced neurodegeneration

From College To Jobs: Making Sense of Labor Market Returns To Higher Education

This report summarizes key findings from recent research on links between higher education and the workforce. Featuring eight brief papers from leading education and workforce experts from around the country, the report offers practical advice for institutional leaders, policymakers, students and their advisers about how to use the increasingly available information on the economic value of higher education. Specifically, the authors' papers and the opening summary explore what various audiences can learn from emerging evidence about: variations in labor market outcomes by program and institution; the value of degrees to jobs both in and out of fields studied; returns to the completion of certain course clusters that don't add up to a degree; and distortions that may result from examining returns to individual degrees rather than "stacked" degrees

The XMM Cluster Survey: The interplay between the brightest cluster galaxy and the intra-cluster medium via AGN feedback

Using a sample of 123 X-ray clusters and groups drawn from the XMM-Cluster Survey first data release, we investigate the interplay between the brightest cluster galaxy (BCG), its black hole, and the intra-cluster/group medium (ICM). It appears that for groups and clusters with a BCG likely to host significant AGN feedback, gas cooling dominates in those with Tx > 2 keV while AGN feedback dominates below. This may be understood through the sub-unity exponent found in the scaling relation we derive between the BCG mass and cluster mass over the halo mass range 10^13 < M500 < 10^15Msol and the lack of correlation between radio luminosity and cluster mass, such that BCG AGN in groups can have relatively more energetic influence on the ICM. The Lx - Tx relation for systems with the most massive BCGs, or those with BCGs co-located with the peak of the ICM emission, is steeper than that for those with the least massive and most offset, which instead follows self-similarity. This is evidence that a combination of central gas cooling and powerful, well fuelled AGN causes the departure of the ICM from pure gravitational heating, with the steepened relation crossing self-similarity at Tx = 2 keV. Importantly, regardless of their black hole mass, BCGs are more likely to host radio-loud AGN if they are in a massive cluster (Tx > 2 keV) and again co-located with an effective fuel supply of dense, cooling gas. This demonstrates that the most massive black holes appear to know more about their host cluster than they do about their host galaxy. The results lead us to propose a physically motivated, empirical definition of 'cluster' and 'group', delineated at 2 keV.Comment: Accepted for publication in MNRAS - replaced to match corrected proo

Characterization of a Novel STAT 2 Knock Out Hamster Model of Crimean Congo Hemorrhagic Fever Virus Pathogenesis

Crimean-Congo hemorrhagic fever virus (CCHFV) is a tick-borne pathogen causing a febrile illness in humans, which can progress to hemorrhagic manifestations, multi-organ failure, and death. Current mouse models of CCHFV infection reliably succumb to virus challenge but vary in their ability to reflect signs of disease similar to humans. In this study, we established a signal transducer and activator of transcription 2 (STAT2) knockout hamster model to expand the repertoire of animal models of CCHFV pathogenesis that can be used for therapeutic development. These hamsters demonstrated a systemic and lethal disease in response to infection. Hallmarks of human disease were observed including petechial rash, blood coagulation dysfunction, and various biochemistry and blood cell count abnormalities. Furthermore, we also demonstrated the utility of this model for anti-CCHFV therapeutic evaluation. The STAT2 knock-out hamster model of CCHFV infection may provide some further insights into clinical disease, viral pathogenesis, and pave the way for testing of potential drug and vaccine candidates

East Chisenbury Midden 2015−17: further investigations of the late prehistoric midden deposits, enclosure and associated settlement

After a gap of almost two decades further investigations were initiated at this remarkable late prehistoric midden site, supported by Operation Nightingale/Breaking Ground Heritage. Geophysical survey clarified the extent of the broadly contemporary enclosure surrounding the midden, as well as other related features, while subsequent excavations provided new information on the midden, the enclosure and settlement. Two small trenches in the northeast half of the midden revealed a different sequence and produced far fewer finds than the 1992−3 excavations in the southwest half, demonstrating that it is not a homogeneous mound. A substantial ditch and associated bank, largely levelled by the late Roman period, may have been contemporary with or pre-dated the early development of the midden, while some 150 postholes attested to the presence of numerous roundhouses and other structures within the enclosure. Overall, a date range of c. 1000−500 cal. BC and possibly later is suggested from radiocarbon dating and pottery, the main phase of midden development perhaps later than the majority of the settlement. Furthermore, recent results of radiocarbon dating of material from the earlier excavations suggest the site sequence may continue as late as c. 400 cal. BC. Radiocarbon dating of the few human remains has also highlighted the likelihood that some were curated, the probable intervals between the dates of death and deposition ranging from a few decades to three centuries. Finds and environmental assemblages are generally consistent with those previously found, but a few sherds of scratch cordoned bowl represent a significant new discovery, as does a unique copper alloy ‘pendant’ of possible continental origin. Evidence now indicates that cattle, as well as sheep and pigs, were intensively managed and slaughtered on site, with the isotope data suggesting local origins for most of the animals, though some cattle may have been raised on pasturage further afield