Microbiologically active environments, like oil reservoirs, can suffer a range of problems due to the presence of sulfate-reducing microorganisms. These include, but are not limited to: H2S ...formation, souring and corrosion. To prevent biogenic sulfate reduction, nitrate can be used as an environmentally friendly alternative to biocides. However, side effects of nitrate injection are sometimes observed but not well understood. In our study, we used original water from an onshore reservoir, where a microbial enhanced oil recovery (MEOR) application is planned, and investigated the effects of nitrate addition on H2S generation, mineral precipitation and microbiology. We observed that nitrate did inhibit H2S formation in most, but not all cases. During nitrate reduction, iron and calcite minerals precipitated over short- and long-term (10 or 160 days) incubations. This was caused by a nitrate-reducing group of bacteria belonging to the family Deferribacteraceae. Using dynamic sandpack setups and numerical modeling approaches with the simulator TOUGHREACT, we observed significant reduction in permeabilities (∼44×) suggesting injectivity issues over time in case nitrate is continuously added to the reservoir. Our study shows that nitrate-dependent processes, which were described separately for pure-cultures before, are also valid for natural mixed communities present in oil fields and underlines the complex interplay of microbial metabolisms associated with those communities.
•Nitrate addition to reservoir water induced iron and calcite mineral precipitation.•The minerals were microbially induced by nitrate-reducing bacteria.•Mineral precipitation during nitrate treatment led to reduction of permeability.
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•Microbial Enhanced Oil Recovery with Halanerobium sp. was performed in sandpacks.•Sucrose consumption with 10 % carbonate was 8 times higher compared to pure quartz.•1 % of carbonate ...and sulfide maintained microbial growth and led to 21.6 % more oil.•Superficial mineral dissolution by microbially produced acids was confirmed by XPS.•Acid neutralization capacity of rock is proposed as a screening criterion for MEOR.
Microbial enhanced oil recovery (MEOR) is an economically attractive tertiary recovery technique and fermentative bacteria are frequently suggested for MEOR, partly because microbially produced organic acids have the potential for rock matrix dissolution.
In this study, the metabolic activity and the community shift of a diverse microbiome of a high-salinity oilfield upon supplying MEOR nutrients was investigated in dynamic sandpacks set-up with and without crude oil using pure quartz sand and two types of reservoir rock. Geochemical characterization of the porous media included specific surface area (SSA), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). During the experiments, substrate and metabolites, incremental oil and differential pressure were monitored and the microbial community shift was investigated via Illumina sequencing.
Fermentative Halanaerobiales outcompeted other microbes and led to an incremental oil recovery of 24.5 ± 9.6%OOIP in reservoir rock. Microbial-induced dissolution of surface minerals was indicated by a decrease in SSA and surface-bound ferrous iron and concluded to be an important MEOR mechanism. Fermentation of sucrose was primarily limited by an insufficient acid neutralization capacity (ANC), but a carbonate content of 12% sustainably buffered the pH in a favorable growth range. Even minor amounts of other non-inert minerals (1% pyrite and calcite) facilitated microbial growth significantly, resulting in six-fold higher acetate production rates compared to quartz sand. Besides emphasizing the relevance of accessory minerals in MEOR, our results imply that the ANC could serve as potential screening parameter for predicting the performance of fermentation-based MEOR in the field.
The majority of Escherichia coli strains isolated from urinary tract infections have the potential to express multiple fimbriae. Two of the most common fimbrial adhesins are type 1 fimbriae and ...pyelonephritis-associated pili (Pap). Previous research has shown that induced, plasmid-based expression of a Pap regulator, papB, and its close homologues can prevent inversion of the fim switch controlling the expression of type 1 fimbriae. The aim of the present study was to determine if this cross-regulation occurs when PapB is expressed from its native promoter in the chromosome of E. coli K-12 and clinical isolates. The regulation was examined in three ways: (1) mutated alleles of the pap regulatory region, including papB and papI, that maintain the pap promoter in either the off or the on phase were exchanged into the chromosome of both E. coli K-12 and the clinical isolate E. coli CFT073, and the effect on type 1 fimbrial expression was measured; (2) type 1 fimbrial expression was determined using a novel fimS : : gfp(+) reporter system in mutants of the clinical isolate E. coli 536 in which combinations of complete fimbrial clusters had been deleted; (3) type 1 fimbrial expression was determined in a range of clinical isolates and compared with both the number of P clusters and their expression. All three approaches demonstrated that P expression represses type 1 fimbrial expression. Using a number of novel genetic approaches, this work extends the initial finding that PapB inhibits FimB recombination to the impact of this regulation in clinical isolates.
As a dynamic screening tool for a high-salinity oilfield (186 g/L), anaerobic sandpacks were established to simulate Microbial Enhanced Oil Recovery (MEOR) under defined laboratory conditions. Glass ...beads, quartz sand or crushed reservoir rock were used to produce porous media which varied in permeability, wettability, homogeneity and geochemistry. In total, 14 sandpacks were flooded with oil and inoculated with indigenous fermentative bacteria of the order Halanaerobiales. After waterflooding, these were treated with nutrients in different injection scenarios during which incremental oil recovery, permeability, microbial activity and produced metabolites were measured.
Our results indicate that the efficiency of MEOR is dependent on the type of porous medium used: Both glass beads and outcrop quartz sand were found to be no suitable analogue to reservoir material because not all potential MEOR effects were accounted for. MEOR was least efficient in quartz sandpacks with a recovery factor of 7.0 ± 1.7% with respect to the original oil in place (IRFOOIP), attributed mainly to fluid-fluid interactions. In sandpacks with reservoir rock, wettability alteration, matrix dissolution and bioplugging were additional MEOR mechanisms and resulted in an incremental recovery which was almost three-fold higher compared to pure quartz sandpacks (IRFOOIP = 23.2 ± 6.4%).
Bioplugging was not detected in sandpacks with a permeability of 8–10 D, although cell retention was observed. Mean pore sizes of these sandpacks were calculated to be in the range of 100 μm, thus considered to be too large to allow for significant plugging. Our findings support the use of MEOR as potential tertiary recovery method but also emphasize the importance of carefully designing laboratory experiments. We argue that porous medium properties such as permeability, pore size, wettability and mineralogy play a crucial role during dynamic MEOR feasibility studies, because they directly influence incremental recovery.
•Bacteria of the genus Halanaerobium were tested for MEOR in dynamic and anaerobic sandpacks at 180 g*L-1 salinity•14 experiments with four different porous media (glass beads, quartz sand and two reservoir rock samples) were conducted•Incremental recovery was three-fold higher in reservoir rock sandpacks (IRFOOIP = 23.2 ± 6.4 %) compared to pure quartz sand•Pure outcrop quartz sand did not meet requirements for all potential MEOR effects to occur•A wettability change from oil- towards water-wet was identified as one of the main MEOR effects
The increasing demand for oil and also increasing numbers of mature oil reservoirs have attracted attention to enhanced oil recovery (EOR) in which microbial enhanced oil recovery (MEOR) is one of ...the commercial options. In order to develop a MEOR strategy for a given field it is extremely important to evaluate the microbial community present, as this will be the basis for a customized nutrient mixture. The objective of this study was to assess how sampling strategies (surface vs. subsurface) can accurately reflect the microbial community and microbial activity in a reservoir. In addition to fluid samples the analysis of sand deposits, also collected from the well bottom, was included to get insight into presence and identity of attached microbes. Fluid samples were collected at the wellhead (surface) and in-situ at a depth of approximately 780m tvdss (true vertical depth subsea) under a reservoir pressure of 31 bars (subsurface). The pressure was released either quickly (within minutes) or slowly (stepwise, within 11 days) to assess the potential activity loss of microorganisms sensitive towards rapid pressure changes. Quantitative PCR (polymerase chain reaction) for determining cell numbers showed higher amounts of microbial cells in the subsurface sample compared to the surface water. The composition of the microbial community was only slightly more diverse in the subsurface sample than in the surface sample. Sand material, however, showed the most diverse community. Biogenic CO2 formation rates were determined under atmospheric and high pressure conditions with highest rates, i.e. highest microbial activity, in the wellhead fluid and the solid sand sample. In conclusion no substantial differences were observed between fast and slowly depressurized subsurface fluids and also between surface and subsurface fluid samples in terms of microbiological activity and diversity. Therefore, using wellhead fluids for microbiological analysis and MEOR development seems to be a valid option although it has always to be carefully considered not to miss out on information of solid samples regarding various aspects such as community and biofilm formation.
•MEOR surface vs. subsurface samplings for an oil reservoir are presented.•Subsurface sampling has no significant improvement on the microbiological analysis.•Very rapid depressurization during sampling should be avoided.•Surface sample contains similar microbial community compared to the subsurface one.•Surface samples can be assumed to be representative for the field studied.
Südafrika hat als weltweit erster Staat den Diskriminierungsschutz aufgrund der sexuellen Orientierung verfassungsrechtlich verankert, gleichzeitig hat das Land ein massives Gewaltproblem, das sich ...in Form von sogenannter Hassgewalt explizit auch gegen LSBTI-Menschen richtet. Die vorliegende Arbeit untersucht, wie sich die südafrikanische Zivilgesellschaft gegen Hassgewalt an LSBTI-Menschen organisiert und welche Rolle hierbei transregionale Akteure spielen. Über eine vergleichende Analyse der Triple Seven-Kampagne (2007-2009) und der Hate Crimes Working Group (seit 2009) werden 14 Jahre südafrikanischer LSBTI-Aktivismus in den Blick genommen und mittels Konzepten aus der sozialen Bewegungsforschung untersucht. Dabei fußt die Untersuchung auf der Annahme, dass sich das Handeln der südafrikanischen Aktivistinnen und Aktivisten nur adäquat verstehen lässt, wenn in die Analyse systematisch eine transregionale Perspektive eingeht. Daten wurden im Zuge von drei Forschungsaufenthalten in Südafrika in den Jahren 2008, 2009 und 2019 erhoben.:1. Einleitung 6
1.1 Forschungsfragen und wissenschaftlicher Forschungsstand 9
1.2 Der theoretische Rahmen 15
1.2.1 Konzepte der sozialen Bewegungsforschung 15
1.2.2 Transregionales und transnationales Forschungsprogramm 18
1.3 Der methodische Ansatz 24
1.3.1 Einzelfallanalyse mit diachronem Vergleich 24
1.3.2 Kontextualisierung der Untersuchungsfälle 27
1.3.3 Postkoloniale Methoden im Kontext qualitativer Sozialforschung 34
1.4 Aufbau der Arbeit 44
2. Kontextualisierung: SOGIESC-Rechte in Südafrika 46
2.1 Zivilgesellschaftliches Engagement für SOGIESC-Rechte 46
2.1.1 Aktivismus für SOGIESC-Rechte im historischen Kontext 46
2.1.2 Charakterisierung der NGO-Landschaft 2007-2020 52
2.2 Zwischen Anspruch und Wirklichkeit:
SOGIESC-Rechte im Zeitraum 2007-2020 58
2.2.1 Der gesellschaftspolitische Rahmen 58
2.2.2 Gewalt gegen LSBTI-Menschen 64
2.3 Südafrikas internationale SOGIESC-Außenpolitik 69
2.3.1 Südafrikanisches Engagement im UN-Menschenrechtssystem 69
2.3.2 Erklärungsansätze 74
2.4 Zusammenfassung 77
3. Die Triple Seven-Kampagne (2007-2009) 79
3.1 Die Gründung der Triple Seven-Kampagne 79
3.1.1 Erfolgreiches Agenda-Setting 79
3.1.2 Menschenrechte als Legitimierungsquelle 84
3.2 Die Triple Seven-Kampagne und transregionale Koalitionen 87
3.2.1 Strategische Ausrichtung und Organisation 87
3.2.2 Transregionale Koalitionen 92
3.3 Die Bedingungen für transregionale Koalitionen 100
3.3.1 Blockierte politische Opportunitätsstruktur 101
3.3.2 Kontakte 105
3.3.3 Emotionale Unterstützung 106
3.3.4 Unterstützung der Kampagnenarbeit vor Ort 108
3.3.5 Partnerschaftliche Zusammenarbeit 109
3.3.6 Ressourcen 111
3.4 Zusammenfassung 116
4. Die Hate Crimes Working Group (2009-2020) 119
4.1 Die Gründung der Hate Crimes Working Group 119
4.1.1 Erfolgreiches Agenda-Setting 119
4.1.2 Hassverbrechen als strategische Klammer 123
4.2 Die Hate Crimes Working Group und transregionale Koalitionen 126
4.2.1 Strategische Ausrichtung und Organisation 127
4.2.2 Transregionale Koalitionen 134
4.3 Die Bedingungen für transregionale Koalitionen 138
4.3.1 Blockierte politische Opportunitätsstruktur 138
4.3.2 Kontakte 143
4.3.3 Emotionale Unterstützung 144
4.3.4 Unterstützung der Kampagnenarbeit vor Ort 146
4.3.5 Partnerschaftliche Zusammenarbeit 147
4.4 Zusammenfassung 153
5. Vergleichende Diskussion der Untersuchungsergebnisse 157
5.1 SOGIESC-Aktivismus und transregionale Koalitionen
im Zeitraum 2007-2020 157
5.1.1 SOGIESC-Rechte in Südafrika 157
5.1.2 Kontinuitäten und Brüche: 14 Jahre SOGIESC-Aktivismus
in Südafrika 159
5.1.3 Die Bedeutung transregionaler Beziehungen im
diachronen Vergleich 163
5.2 Grenzen der Studie und Forschungsdesiderata 171
6. Bibliographie 175
6.1 Quellen 175
6.2 Literatur 192
Anhang 1: Interviews 202
Abstract
We present strong gravitational lensing models for 37 galaxy clusters from the Sloan Digital Sky Survey Giant Arcs Survey. We combine data from multi-band
Hubble Space Telescope
Wide Field ...Camera 3 (WFC3) imaging, with ground-based imaging and spectroscopy from
Magellan
, Gemini, Apache Point Observatory, and the Multiple Mirror Telescope, in order to detect and spectroscopically confirm new multiply imaged lensed background sources behind the clusters. We report spectroscopic or photometric redshifts of sources in these fields, including cluster galaxies and background sources. Based on all available lensing evidence, we construct and present strong-lensing mass models for these galaxy clusters. The clusters span a redshift range of 0.176 <
z
< 0.66 with a median redshift of
z
= 0.45, and sample a wide range of dynamical masses, 1.5 <
M
200
< 35 × 10
14
, as estimated from their velocity dispersions. As these clusters were selected as lenses primarily owing to a fortuitous alignment with background galaxies that results in giant arcs, they exhibit a wide range in Einstein radii, 1.″3 <
θ
E
< 23.″1 for a source at
z
= 2, with a median
θ
E
= 10.″8. The reduced
HST
images and lens model outputs are made available to the scientific community as high-level data products with this publication.
Coercive measures (CM) in psychiatry adversely affect patients and efforts to minimize CM are steadily increasing. One area that has not been a strong focus of preventative efforts to date is the ...time of use of CM during hospitalization although previous research indicates that the admission situation and early hospitalization are times of increased risk for CM. This study therefore aims to contribute to the body of research in this field by analyzing in detail the times of use of CM and identifying patient characteristics serving as predictors for CM during early hospitalization. Using a large sample (N = 1556) of all cases admitted in 2019 via the emergency room at the Charité Department of Psychiatry at St. Hedwig Hospital in Berlin, this study supports previous research showing that the risk of CM is highest within the first 24 h h of hospitalization. Of 261 cases who experienced CM, 71.6% (n = 187) experienced a CM within the first 24 h of hospitalization and 54.4% (n = 142) of cases only experienced CM within the first 24 h of hospitalization and did not receive any CM after. Furthermore, this study identified significant predictors for the early use of CM during hospitalization including acute intoxication (p < .01), aggression (p < .01), male gender (p < .001) and limited communication ability (p < .001). The results highlight the importance of directing preventative efforts to minimize the use of CM not only to psychiatric units but also to mental health crisis response and to develop interventions specifically tailored to this time and patient groups at highest risk.
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