1,002 research outputs found
Ein hardground am Top eines kalkigen Tempestits im Mittleren Kimmeridge auf dem Kalkrieser Berg (Nordwestdeutschland)
The tempestite origin of the upper part of the Zwischenbank (Mittelkimmeridge VII, Upper Jurassic) in the Kalkrieser Berg (Southwestern Lower Saxony) is explained by means of microlacial, paleontological and sedimentological analyses. At the top of the limestone, a hard ground was lormed and, at a later stage, exposed by erosion and then colonized;its environment was shallow marine nearshore. This is the lirst description of the origin of a German Jurassie hard ground s. s. and an Upper Jurassie calcareous tempestite.Anhand mikrolazieller, paläontologischer und sedimentologischer Untersuchungen wird die tempestitische Natur des oberen Teils der Zwischenbank (Mittelkimmeridge VII, Oberer Jura) am Kalkrieser Berg (SW-Niedersachsen) dargelegt. An der Oberkante der Kalkbank ist ein hardground ausgebildet, der erosiv Ireigelegt und anschließend besiedelt wurde. Das Milieu stellt sich als Ilachmarin und küsten nah dar. Die Arbeit ist die erste Beschreibung der Genese eines deutschen jurassischen hardgrounds s. s. und der erste Nachweis eines kalkigen oberjurassischen Tempestits
Mechanisms and Regulation of Aerobic Respiration in Shewanella Oneidensis MR-1
Shewanella oneidensis MR-1 expresses three terminal oxidase complexes predicted to participate in aerobic respiration: an aa3-type cytochrome c oxidase, a cbb3-type cytochrome c oxidase, and a bd-type quinol oxidase. An intermediate bc1 complex is used for transfer of electrons to the aa3-type and cbb3-type cytochrome c oxidase complexes. Use of the terminal aerobic oxidases in S. oneidensis is atypical. The aa3-type cytochrome c oxidase is the expected primary oxidase complex in oxygen-replete conditions; however, it has no observed function in aerobic growth in S. oneidensis. The cbb3-type cytochrome c oxidase and bd-type quinol oxidase are the primary oxidases used for aerobic respiration in this organism, regardless of oxygen tension. The regulatory systems CRP, a cyclic AMP (cAMP) binding protein, and the ArcAB two-component system regulate anaerobic respiration and appear to play a role in aerobic growth if S. oneidensis. Furthermore, the S. oneidensis the cyclic AMP phosphodiesterase, cpdA (SO_3901) also appears to affect aerobic growth, but its exact role in this process is not known. .
This work analyzes aerobic growth of mutants deficient in terminal oxidase complexes and regulatory proteins when exposed to different sole carbon sources in basal medium. A deletion mutant of both the bc1 complex and the bd-type quinol oxidase exhibited a severe growth deficiency under all conditions tested. Mutants deficient in CRP and ArcA demonstrated slight aerobic growth deficiencies. The cpdA mutant demonstrated a severe growth deficiency. Carbon source does not drastically affect the growth phenotype of mutants tested. In this work, aerobic growth of two CRP-like proteins (SO_2550 and SO_2551) was also analyzed. These proteins contain the cyclic nucleotide binding domain as well as the helix-turn-helix motif of CRP-family proteins. Deletion of genes that encode these proteins results in an aerobic growth deficiency. We also analyzed promoter expression of the two major aerobic terminal oxidase complexes in these regulatory protein deletion mutants. To assess promoter expression over time, a fluorescent timer system was developed using a mutant mCherry that fluoresces blue after translation and matures to red. This system allows analysis of growth and promoter expression simultaneously. Promoter expression did not drastically change during the growth cycle of S. oneidensis, confirming that growth deficiencies of regulatory system mutants are not due to lack of expression of terminal oxidase complexes.
Recovery of the growth deficiency of the cpdA deletion mutant was also analyzed in this work. Addition of casamino acids to a basal medium restored aerobic growth in this mutant. Growth of a cpdA deletion mutant was also restored by the inactivation of SO_3550 (an anti- sigma factor). The SO_3550 cognate sigma factor encoded by SO_3551 is an ECF, or extracytoplasmic function sigma factor. ECF sigma factors are typically used in stress response in bacteria, suggesting that the action of this sigma factor is able to remedy the growth deficiency of the cpdA mutant
Middle School Students\u27 Empathy with the Environment throughout a Critical Place-Based Art Program
The ecological imagination calls for a new mode of education: education that embraces the arts as a way to conceive of new ecological perspectives, other ways of being in relation to the earth, better ecological alternatives, and new dialogues about our role in the world. Through a critical place-based art pedagogy, education can become a means of awakening the ecological imagination—opening the world to new possibilities, new critiques, and, most importantly, new acts. Empathy is especially appropriate to study as an outcome of a critical place-based art program because of its ability to facilitate connections and its close ties with aesthetic experience. Thus, the purpose of this ongoing mixed methods case study is to examine how middle school students in a critical place-based art program experience empathy with the environment. Operating in the pragmatic paradigm, the study asks the following questions: How do middle school students experience empathy with the environment throughout a critical place-based art program? How does participation in a place-based art education program affect students’ pro-environmental orientations (ecological paradigm)? Which aspects of a place-based art education program, if any, contribute to students’ empathy with the environment? Why? Drawing exercises, interviews, surveys, reviews of visual/verbal journals, observations, and focus groups will be used to answer these questions. This study is especially relevant for art educators and administrators seeking to develop programs that are relevant to students and capable of producing empathetic, ecologically-minded, active citizens who are capable of working toward social and ecological change in their communities
Human Rights and the Current Immigration Debate: Legislative Proposals\u27 Effects on the Mexican Immigrant Population
From Sharks to The Big Ugly
This longitudinal case study explored one rural elementary art teacher’s praxis for two years after she participated in professional development sessions on place-based education (PBE). These sessions focused specifically on PBE within the discipline of art for K-12 art educators in a geographically-large southeastern school district. Through surveys, observations, interviews, and document analysis of curricular materials, the researchers investigated the teacher’s experiences with PBE as she taught art in a rural area of the district. Her curricular decisions transitioned from a focus on art reflecting her personal knowledge base to art that built on students’ expressions of, experiences in, and knowledge of, their rural setting. Implications for teacher professional development focused on rural education include strategies for promoting the contextualization of content and communicating the benefits of transitioning from place-neutral to place-based instruction
EXPLORING THE BUSINESS VALUE OF SOFT SKILLS IN SOCIAL NETWORKS – A CONCEPTUAL EVALUATION APPROACH BASED ON CONSENSUS SCORING
Since the emergence of the Internet era in the early 1990s, many evaluation systems for the rating of various entities emerged. For example, at amazon.com people are able to rate books and transactions or to leave comments for other users. Although there is a wide variety of rating and evaluation mechanisms on the Internet, there are only few mechanisms for the evaluation of user skills in social networks. For many users online profiles displaying other people’s skills are increasingly important, e. g., when contracting freelancers or finding candidates for a job opening. However, current profiles found in social networks offer either unstructured free text that is hard to handle efficiently or simplistic rating schemes that do not convey meaningful information. In addition, it is unclear how trustworthy the information on the profile is. Hence, in this paper, we provide a novel approach for the evaluation of soft skills on the Internet. Our approach is based on a consensus measurement approach in social network services based on social graphs as a formalization of personal relationships among users
Aerobic Respiration and Its Regulation in the Metal Reducer Shewanella Oneidensis
Shewanella oneidensis MR-1 is a facultative anaerobe known for its ability to reduce metal oxides. Anaerobic respiration, especially metal reduction, has been the subject of extensive research. In contrast, S. oneidensis aerobic respiration has received less attention. S. oneidensis expresses cbb3- and aa3-type cytochrome c oxidases and a bd-type quinol oxidase. The aa3-type oxidase, which in other bacteria is the major oxygen reductase under oxygen replete conditions, does not appear to contribute to aerobic respiration and growth in S. oneidensis. Our results indicated that although the aa3-type oxidase does not play a role in aerobic growth on lactate, the preferred carbon source for S. oneidensis, it is involved in growth on pyruvate or acetate. These results highlight the importance of testing multiple carbon and energy sources when attempting to identify enzyme activities and mutant phenotypes. Several regulatory proteins contribute to the regulation of aerobic growth in S. oneidensis including CRP and ArcA. The 3\u27,5\u27-cAMP phosphodiesterase (CpdA) appears to play a more significant role in aerobic growth than either CRP or ArcA, yet the deficiency does not appear to be the result of reduced oxidase genes expression. Interestingly, the ΔcpdA mutant was more deficient in aerobic respiration with several carbon sources tested compared to Δcrp, which was moderately deficient only in the presence of lactate. To identify the reason for ΔcpdA aerobic growth deficiency, we isolated a suppressor mutant with transposon insertion in SO_3550. Inactivation of this gene, which encodes an anti-sigma factor, restored aerobic growth in the cpdA mutant to wild-type levels. Inactivation of SO_3550 in wild-type cells, however, did not affect aerobic growth. The S. oneidensis genome encodes two additional CRP-like proteins that we designated CrpB and CrpC. Mutants that lack crpB and crpC were deficient in aerobic growth, but this deficiency was not due to the loss of oxidase gene expression.Keywords: aerobi
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