4,378 research outputs found
Steven Johnson Author Talk Poster
No full textK-State Book NetworkA poster advertising an author talk by Steven Johnson at Kansas State University on September 3, 2014. Steven Johnson's book "The Ghost Map" was the 2014-2015 common book
PHA Production in Aerobic Mixed Microbial Cultures
No full textPolyhydroxyalkanoate (PHA) is a common intracellular energy and carbon storage material in bacteria, which is considered as a bioplastic due to its plastic like properties. PHAs are versatile materials which are biodegradable and made from renewable resources. Commercial production of PHAs is currently based on pure culture processes employing either natural PHA producers or genetically modified bacteria. Pure culture processes use generally pure sterile substrates and axenic reactors, leading to high production costs and thus relatively expensive products. An alternative approach for the production of PHAs is the use of mixed culture biotechnology, using non-sterile waste streams as a substrate and open reactors. The use of cheaper substrates, less energy (no sterilization of substrate or reactors) and cheaper equipment could reduce the production costs compared to pure culture processes. However, the mixed culture PHA production process requires optimization for higher cellular PHA contents to be competitive with pure culture processes. The research described in this thesis aimed at improving the cellular PHA contents that can be achieved in open mixed cultures. A two-step process consisting of (i) a culture enrichment and growth step and (ii) a PHA production step was used. For the enrichment of a mixed culture with PHA producing bacteria a selective pressure in the form of alternating periods of short presence of the carbon substrate (feast phase) and long absence of the carbon substrate (famine phase) under fully aerobic conditions was employed. PHA storing bacteria generally outcompete other bacteria in such a feast-famine system due to their very high substrate uptake rate (which is not limited by the growth rate) and due to the ability to grow in a more balanced way throughout feast and famine phase. A sequencing batch reactor (SBR) was used to establish the feast-famine regime. The cultures enriched in the first step under different operational conditions were tested for their ability to produce PHA in the second step, the PHA production step. For this purpose the cultures were supplied with an excess of carbon source (fed-batch reactor) while withholding a suitable nitrogen source in order to avoid growth and direct as much carbon as possible into PHA storage. To simplify the system for the optimization studies a mineral medium with acetate as the sole carbon substrate was used in all experiments rather than real wastewater. Acetate yielded pure polyhydroxybutyrate (PHB) as the storage polymer. In order to compare different operational conditions, specific reaction rates and observed yields had to be calculated for the key compounds acetate, biomass, PHB, carbon dioxide, oxygen and the nitrogen source ammonia from measurements performed during a stable SBR cycle or fed-batch experiment. Both SBR and fed-batch reactor were highly dynamic systems with changing reaction rates and liquid volumes, making the evaluation of experimental data a complex task. A very detailed data analysis was carried out for each SBR cycle measurement and fed-batch experiment. The data analysis included for example the correction of measurements for sampling effects and liquid volume changes, the computation of oxygen consumption and carbon dioxide evolution, and the calculation of the best estimates for all reaction rates and total conversions at each time point with the help of a metabolic model (Chapter 2). The metabolic model was used in order to be able to describe the dynamics of the system and in order to ensure that material balances would close. The metabolic model described the measurements generally very well. The reaction rates computed with the metabolic model showed clearer trends than those calculated without the help of the model. Different operational conditions were tested for the biomass enrichment step (SBR). The first two process parameters investigated were low sludge residence times (SRTs) of 4 d, 1 d and 0.5 d and the impact of different degrees of nitrogen versus carbon limitation (Chapter 3). Low SRTs are required for a high biomass productivity in the first step. The impact of nitrogen limitation was investigated, because many waste streams that are suitable substrates for mixed culture PHA production are nutrient limited. Enrichment of a PHA storing community was successful at 4 d and 1 d SRT, but less successful at 0.5 d SRT. Nitrogen limitation in the SBR generally led to competition for nitrogen and consequently to a selective pressure for high growth rates. Carbon limitation in the SBR led to a PHB storage strategy (high acetate uptake rate) and usually to higher PHB contents (about 70 wt%) in subsequent fed-batch experiments compared to cultures enriched under nitrogen limitation. Carbon limitation in the SBR allowed PHB storing bacteria to benefit more from their ability to store PHB by being able to grow throughout the famine phase. Carbon limitation and SRTs higher than 0.5 d were identified as favourable conditions for the biomass enrichment step in the SBR. Nutrient limited wastewaters may require supplementation with nutrients for this step. Another parameter that was investigated was the reactor temperature (Chapter 4). The reactor temperature will influence the reaction rates, but also the selective pressure in the SBR. The influence on the reaction rates can be investigated by applying short-term temperature changes (i.e. one SBR cycle) while the combined effect on reaction rates and selective pressure can be studied in long-term temperature change experiments. In short-term temperature change experiments the reactor temperature of a stable SBR operated at 20°C was changed for one cycle to 15, 25, 30 or 35°C. It was found that reaction rate changes in the famine phase could be described over the whole temperature range with the Arrhenius equation with one temperature coefficient. For the feast phase different temperature coefficients were estimated for acetate uptake, PHB production and growth. These were only valid for temperatures 5°C higher or lower than the steady state temperature. After long-term changes to either 15 or 30°C the reactor performance changed considerably: At lower temperatures the feast phase was long and a growth strategy prevailed. This culture had a very low PHB storage capacity (about 35 wt%). At 30°C the feast phase was short and a PHB storage strategy dominated. This culture was able to store 84 wt% PHB. Higher SBR temperatures appear to be a good strategy to support the enrichment of PHB storing bacteria. In Chapter 5 we report the most successful operating strategy applied during this thesis. A SBR culture was enriched that was able to store 89 wt% PHB within only 7.6 h in a fed-batch experiment. This culture had been enriched with a longer cycle length of 12 h as compared to our previous studies (4 h cycle length), at 1 d SRT, 30°C and carbon limitation. Another key to the high PHB content was the long operating time under these conditions of over a year. The maximum PHB storage capacity of this culture had improved with time. The long cycle length combined with a low SRT was found to favour growth of bacteria that can store a high amount of PHB at a high rate, since this is needed in order to continue to grow throughout the much longer famine phase. After the operating conditions in the SBR had been optimized, also the PHA production step in the fed-batch reactor was investigated. The temperature in fed-batch experiments did not influence the maximum PHB storage capacity, but only the reaction rates (Chapter 4). Fed-batch experiments were typically conducted using fed-batch systems without nitrogen source in the feed. With the aim of using waste streams as a substrate for PHA production, nutrient limitation or starvation may not always be feasible. We therefore investigated the influence of nitrogen starvation, nitrogen limitation and nitrogen excess on the maximum PHB content obtained in fed-batch experiments (Chapter 6). Under nitrogen starvation conditions the biomass reached a maximum PHB content of 89 wt%, under nitrogen limitation 77 wt% and under nitrogen excess 69 wt%. In the latter two experiments PHB contents decreased after these maxima were reached, because growth led to a dilution of the PHB pool. Nutrient starvation seems thus to be the best strategy for maximal PHB production in the fed-batch step. Chapter 7 summarizes and integrates the findings from all individual studies. In this chapter also some remaining issues are discussed and recommendations for future research are provided. With the aim of using real waste streams in the future and producing other PHAs apart from PHB, the next steps would be the use of more diverse carbon source mixtures and eventually a scale-up of the system. In conclusion, mixed culture PHB production has been successfully optimized in this thesis. A mixed culture was established with the capacity to produce PHB levels as high as in pure culture production processes, and at very high PHB production rates. Cultivation conditions have been identified that lead to a selection of a stable mixed microbial culture with a superior PHA production capacity. Compared to previous work with mixed cultures, a more than four times higher cellular PHB content was obtained. Herewith a highly competitive process has been established that may contribute to the development of a more sustainable and renewable biopolymer production in a future bio-based economy.BiotechnologyApplied Science
LGBTI variations in crime reporting: how sexual identity influences decisions to call the cops
No full textResearch shows that people vary in their willingness to report crime to police depending on the type of crime experienced, their gender, age, and their race or ethnicity. Whether or not lesbian, gay, bisexual, transgender, and intersex (LGBTI) and heterosexual people vary in their willingness to report crime to the police is not well understood in the extant literature. In this article, I examine variations in LGBTI respondents' attitudes, subjective norms, and perceived behavioral control on their intentions to report crimes to the police. Drawing on a survey of LGBTI individuals sampled from a Gay Pride community event and online LGBTI community forums (N = 329), I use quantitative statistical methods to examine whether LGBTI people's beliefs in police homophobia are also directly associated with the behavioral intention to report crime. Overall, the results indicate that LGBTI and heterosexual people differ significantly in their intention to report crime to the police, and that a belief in police homophobia strongly influences LGBTI people's intention to underreport crime to the police
Hector, Johnson County
No full textWill Noonen, “Hector, Johnson County,” Chapman Center Research Collections, https://ccrsresearchcollections.omeka.net/items/show/166.This study focuses on a Post Office community and what defines a community. It focuses on Hector, Johnson County, Kansas from 1856- 1900. The author used newspapers, atlases and plat maps, site work, biographies, and historic photograph collections
Generating the Johnson filtration
No full textFor k 1, let I1g (k) be the kth term in the Johnson ltration of the mapping class group of a genus g surface with one boundary component. We prove that for all k 1, there exists some Gk 0 such that I1g (k) is generated by elements which are supported on subsurfaces whose genus is at most Gk. We also prove similar theorems for the Johnson ltration of Aut(Fn) and for certain mod-p analogues of the Johnson ltrations of both the mapping class group and of Aut(Fn). The main tools used in the proofs are the related theories of FI-modules (due to the rst author with Ellenberg and Farb) and central stability (due to the second author), both of which concern the representation theory of the symmetric groups over Z
Thermal properties of big bluestem as affected by ecotype and planting location along the precipitation gradient of the Great Plains.
No full textThe objective of this research was to study the effect of ecotype and planting location on thermal properties of big bluestem. Three big bluestem ecotypes (CKS, EKS, ILL) and a cultivar (KAW) were harvested in 2010 from four locations (Colby, Hays, and Manhattan, KS; and Carbondale, IL) and were evaluated for their specific heat, thermal conductivity, thermal stability, HHV (high heating value), and proximate contents. All populations revealed a large variation in specific heat (2.35-2.62 kJ/kg/K), thermal conductivity (77.85-99.06 x 10³ W/m/K), thermogravimetric analysis as weight loss during the
heating process (71-73%), and HHV (17.64-18.67 MJ/kg). Specific heat of the big bluestem was significantly affected by planting location, ecotype, and interaction between location and ecotype. Planting location had stronger influence on specific heat than ecotype. Specific heat increased as temperature increased, and a linear correlation model for specific heat prediction was developed as a function of temperature. Ecotype, planting location, and the interaction of ecotype and planting location did not have a significant effect on thermal conductivity; however, density and particle size showed a completely opposite relationship on thermal conductivity. Both planting location and ecotype significantly affected HHV. Among all environmental factors, potential evapotranspiration had the most significant effect on thermal properties
dib-lab/ONT_Illumina_genome_assembly: v1.0.1
No full texttest doi release
Lisa K. Johnson [1,2], Ruta Sahasrabudhe [3], Tony Gill [1], Jennifer Roach [1], Lutz Froenicke [3], C. Titus Brown [2], Andrew Whitehead* [1]
[1] Department of Environmental Toxicology, University of California, Davis [2] Department of Population Health & Reproduction, School of Veterinary Medicine, University of California, Davis [3] DNA Technologies Core, Genome Center, University of California, Davis *corresponding author: [email protected]
Curriculum Studies as an international conversation: cosmopolitanism in a Latin American key
No full textMy work addresses the field of Curriculum Studies as a worldwide interdisciplinary field, its difficulties, complications, and possibilities. It primarily focuses on the relations between the Anglo-Saxon field of Curriculum Studies and the Latin American educational tradition. Looking at these relations from the 1960s to the current moment, I seek to unpack the complexities involved in understanding Curriculum Studies as an international field. Although there are historical and current power dynamics complicating this endeavor, I suggest a possible cosmopolitan project informed by intercultural dialogue.
I develop my understanding of curriculum as currere (Pinar, 1976a, 1976b; Grumet 1976a, 1976b) to inform my dissertation both conceptually and methodologically. I accept Pinar’s conceptualization of the field of Curriculum Studies as a complicated conversation. I situate my joining the conversation in that field from an international point of view, from my Latin American self. It is my own biography that brings this particular conversation into being, with the intention of making life educative. I situate my own educational experience at the center of this inquiry, trying to understand my biographical situation as a Latin American history teacher earning a Ph.d. in Curriculum and Instruction in an American University,a context where my biography intertwines with the field’s history. I move from biography to history in a conversation where personal troubles become public issues, biography and history intertwine, and the struggle for a better life emerges with ethical urgency.
Methodologically, I suggest a variant of the regressive-progressive-analytical-synthetical method currere. I tie each of these four moments of currere to a specific decade in my life and in the history of the field in the United States and Latin America. The regressive moment, the time of the given, is tied to the 1960s, when the field of curriculum arrived and was in tension with the progressive moment, which is tied to the 1990s and the problem of ‘the other’ that emerged around the commemoration of 1492. The analytical is the 2000s, in which the decision to devote myself to the field of education was put into tension with the synthetical, which refers to the current moment, the 2010s, when I advocate the study of Curriculum Studies. From there, I propose my version of a cosmopolitan project in Curriculum Studies, a cosmopolitanism that I can only sing in a Latin American key.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2018-12-01The student, Daniel Johnson Mardones, accepted the attached license on 2016-11-15 at 13:53.The student, Daniel Johnson Mardones, submitted this Dissertation for approval on 2016-11-15 at 14:07.This Dissertation was approved for publication on 2016-11-17 at 14:59.DSpace SAF Submission Ingestion Package generated from Vireo submission #10249 on 2017-02-28 at 14:41:33Made available in DSpace on 2017-03-01T17:01:17Z (GMT). No. of bitstreams: 2
JOHNSONMARDONES-DISSERTATION-2016.pdf: 1705763 bytes, checksum: 8058c0c85a8a626b3568cd725068a791 (MD5)
LICENSE.txt: 4220 bytes, checksum: aae1cbe904a25c149ed400ecefccbfce (MD5)
Previous issue date: 2016-11-17Embargo set by: Seth Robbins for item 98687
Lift date: 2019-03-01T17:02:22Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 98687
Lift date: 2019-03-01T17:03:32Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 98687
Lift date: 2019-03-01T17:05:02Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 98687
Lift date: 2019-03-01T17:06:55Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemLimited Restriction Lifted for Item 98687 on 2019-03-02T10:15:08Z
Trust and responsibility attributions: variations across hazard managers in accidental and intentional food contamination incidents
No full textSources of trust in hazard managers have been studied in detail over many years, but reasons for attributing responsibility for hazard system performance have not. This study examines the role of factors in the salient value similarity (SVS) and intuitive detection theorists (IDT) models of trust, as well as awareness of problems and freedom to act to deal with those problems (AWFR), in predicting both trust and attributions of responsibility. The context used is a hypothetical contamination of food by Salmonella bacteria, either accidental or intentional, and these judgments are assessed for food producers, processors, "watchdogs" (government), sellers, preparers, and consumers. Results show that trust is primarily positively predicted by an index combining SVS and IDT items, with AWFR playing a trivial role of varying sign. However, initial attributions of responsibility are positively predicted by AWFR, with SVS/IDT as a secondary and largely negative predictor. These relative roles persist in logistic regressions of final attributions of responsibility, which control for the initial attributions. Modest differences occur across hazard managers and contamination cause in both trust and responsibility attributions, but these do not affect the relative influence of SVS, IDT and AWFR variables.Poster presented December 5, 2011 at the 31st annual meeting of the Society for Risk Analysis, Charleston, South Carolina.Peer reviewe
Can\u27t Stand Still : Taylor Gordon and the Harlem Renaissance
No full textBorn in 1893 into the only African American family in White Sulphur Springs, Montana, Emmanuel Taylor Gordon (1893–1971) became an internationally famous singer in the 1920s at the height of the Harlem Renaissance. With his musical partner, J. Rosamond Johnson, Gordon was a crucially important figure in popularizing African American spirituals as an art form, giving many listeners their first experience of black spirituals.
Despite his fame, Taylor Gordon has been all but forgotten, until now. Michael K. Johnson illuminates Gordon’s personal history and his cultural importance to the legacy of the Harlem Renaissance, arguing that during the height of his celebrity, Gordon was one of the most significant African American male vocalists of his era. Gordon’s story—working in the White Sulphur Springs brothels as an errand boy, traveling the country in John Ringling’s private railway car, performing on vaudeville stages from New York to Vancouver to Los Angeles, performing for royalty in England, becoming a celebrated author with a best-selling 1929 autobiography, and his long bout of mental illness—adds depth to the history of the Harlem Renaissance and makes him one of the most fascinating figures of the twentieth century.
Through detailed documentation of Gordon’s career—newspaper articles, reviews, letters, and other archival material—the author demonstrates the scope of Gordon’s cultural impact. The result is a detailed account of Taylor’s musical education, his career as a vaudeville performer, the remarkable performance history of Johnson and Gordon, his status as an in-demand celebrity singer and author, his time as a radio star, and, finally, his descent into madness. Can’t Stand Still brings Taylor Gordon back to the center of the stage.https://scholarworks.umf.maine.edu/publications/1034/thumbnail.jp
- …
