Laminar Micrite Crusts and Associated Foreslope Processes, Red Sea

Forereef slopes in the Red Sea of Sudan exhibit a uniform biozonation that is independent from the topography of the slopes. Below - 120 m, ledges protrude horizontally from sleep cliffs of barrier reefs and atolls as well as from patches of in situ lithified slope sediment on inclined fringing reef slopes. Free surfaces and cavities within these ledges are partly covered by laminar micrite crusts of 7-20 mm thickness. The ledges are formed by an organic framework of living azooxanthellate corals, bryozoans, serpulids and fossil red algae. They are affected by repeated episodes of boring, infilling, and cementation which obliterate much of the original fabric. Concomitant cementation and boring result in asymmetric cement linings which often show geopetal fabrics. The laminar micrite crusts, however, show no significant traces of bioerosion, which are a typical feature of fossil deep-water stromatolites. Two types of lamination have been observed: 1) vertically stacked, irregular, anastomosing laminate with ragged outlines and little lateral persistence which are often accentuated by iron staining, and 2) 0.5-mm-thick laminae of light-grey micrite, rich in fine bioclasts, showing smooth, thin coatings of dark homogenous micrite, which are weakly fluorescent in ultraviolet light. No algal films are preserved, but micritic tubes 10-30 mu m in diameter, often bifurcated, form a dense network on the upper surface of the crusts by overgrowing and binding particles. Associated aragonitic rosettes 30-40 mu m in diameter may represent calcified coccoid algae or bacteria. If true, these organisms suggest a formation of the latter type of crust by biogenic processes not related to the photic zone. Fenestral porosity and Frutexites textures are absent. Radiocarbon dates from corals within the ledges provide ages of 10,500 YBP. From the time-related decrease in oxygen isotope ratios (versus PDB) of boring micrite (delta 18 O = +3.72 per thousand ), micrite crusts (delta 18 O = +1.69 per thousand ), and unlithified mud (delta 18 O = +0.47 per thousand ) within the youngest voids of the hard substrates, we conclude that crust formation must have taken place in shallower water when sea level was lower during the Early Holocene rise of sea level

The foralgal crust facies of the deeper fore reefs in the Red Sea: A deep diving survey by submersible

Autochthonous organic frameworks from the deeper fore reef (−50 m to −110 m) of the Red Sea are composed predominantly of incrusting calcareous red algae and foraminifera. This foralgal crust facies is represented by three types. The first is a pure foralgal crust community which forms small buildups with bumpy surfaces. Calcareous red algae and incrusting formainifera comprise more than 60 % of the biogenous fabric. The second type is a framework in which foralgal crusts are secondary binders around the hermatypic deep water scleractinian Leptoseris fragilis. The third type occurs on drowned reefs, exhibiting a mixture of Pleistocene shallow water and present day deep water binding species. Therefore, the morphology of this subfacies is more governed by an inherited relief, characterized by pinnacles and barrel shaped towers. This present day deep water foralgal community started to develop within the Cretaceous in shallow water environments, composed predominantly of corallinaceans, peyssonneliaceans, and subordinately of acervulinid foraminifera. With the beginning of the Neogene, the shallow water community of reef binding foraminifera and calcareous algae changed and become dominated by the foraminifera Acervulina. The living foralgal crusts of the deeper fore reef in the Red Sea represent a binding community of Upper Cretaceous and Palaeogene shallow water environments which has shifted in greater water depth with time

Hygiene bei der HNO-Untersuchung: Fluoreszenzstudie mit Übersicht der aktuellen Empfehlungen

Zusammenfassung Steigende normative Anspruche an Patientensicherheit und Ma ss nahmen der Qualitatssicherung, aber auch die Problematik multiresistenter Keime und von Erregern mit hohem Ansteckungspotenzial verstarken die Notwendigkeit hygienisch korrekten Arbeitens. In dieser Studie sollten hygienisch relevante potenzielle Kontaminationsquellen bei der HNO-Untersuchung identifiziert und mogliche Verbesserungsstrategien untersucht werden. Von 5 Untersuchern mit unterschiedlicher Berufserfahrung, deren Handschuhe vor der Untersuchung mit Fluoreszenzlotion benetzt wurden, wurde eine komplette HNO-Untersuchung durchgefuhrt. Kontaminierungen insbesondere an der Untersuchungseinheit und am Instrumentarium wurden identifiziert. Das potenzielle Risiko einer ubertragung von Erregern auf Folgepatienten wurde mittels eines eigens entwickelten Scores bewertet. Verschiedene Strategien zur Reduzierung identifizierter Kontaminationsmoglichkeiten wurden erarbeitet und gedanklich durchgespielt. Der Score der Untersucher war mit im Mittel 87,4 Punkten (3,6) sehr hoch. Die Umsetzung von einzelnen Hygienema ss nahmen im Untersuchungsablauf wurde zu einer deutlichen Erniedrigung des Scores und damit einer Verbesserung der Hygiene fuhren: kein Handeschutteln (81,8), zusatzlich Patientenstuhldesinfektion (79,8), Desinfektion wichtiger Flachen (69,8), Bereitstellen von Standardinstrumenten (60,2) oder aller Instrumente (32,2), Desinfektion aller relevanten Flachen und Bereitstellen aller Instrumente (7,4). Die Ergebnisse zeigen sehr deutlich, dass eine HNO-Untersuchung aus Sicht der Hygiene einen komplexen Vorgang darstellt. Fur einen verlasslichen Schutz vor moglichen ubertragungsereignissen ist deshalb eine strukturierte Bundelung von Hygienema ss nahmen notwendig. Abstract Increasing normative demands on patient safety and quality assurance measures, but also the problem of multi-resistant germs and pathogens with a high potential for infection, increase the need for hygienically correct work. In this study, hygienically relevant potential sources of contamination in ENT examinations were to be identified and possible improvement strategies examined. A complete ENT examination was performed by 5 examiners with different professional experience, whose gloves were wetted with fluorescent lotion prior to the examination. Contaminations especially on the examination unit and on the instruments were identified. The potential risk of transmission of pathogens to subsequent patients was assessed using a specially developed score. Various strategies to reduce identified contamination possibilities were developed and thought through. The score of the investigators was very high with an average of 87.4 points (+/- 3.6). The implementation of individual hygiene measures during the examination process would lead to a significant reduction of the score and thus to an improvement in hygiene: No shaking of hands (81.8), additional disinfection of patient's chair (79.8), disinfection of important surfaces (69.8), provision of standard instruments (60.2) or all instruments (32.2), disinfection of all relevant surfaces and provision of all instruments (7.4). The results show very clearly that an ENT examination is a complex procedure from the point of view of hygiene. For reliable protection against possible transmission events, a structured bundling of hygiene measures is therefore necessary

Stable isotope variation in tooth enamel from Neogene hippopotamids : monitor of meso and global climate and rift dynamics on the Albertine Rift, Uganda

The Neogene was a period of long-term global cooling and increasing climatic variability. Variations in African-Asian monsoon intensity over the last 7 Ma have been deduced from patterns of eolian dust export into the Indian Ocean and Mediterranean Sea as well as from lake level records in the East African Rift System (EARS). However, lake systems not only depend on rainfall patterns, but also on the size and physiography of river catchment areas. This study is based on stable isotope proxy data (¹⁸O/¹⁶O, ¹³C/¹²C) from tooth enamel of hippopotamids (Mammalia) and aims in unravelling long-term climate and watershed dynamics that control the evolution of palaeolake systems in the western branch of the EARS (Lake Albert, Uganda) during the Late Neogene (7. 5 Ma to recent). Having no dietary preferences with respect to wooded (C₃) versus grassland (C₄) vegetation, these territorial, water-dependant mammals are particularly useful for palaeoclimate analyses. As inhabitants of lakes and rivers, hippopotamid tooth enamel isotope data document mesoclimates of topographic depressions, such as the rift valleys and, therefore, changes in relative valley depth instead of exclusively global climate changes. Consequently, we ascribe a synchronous maximum in ¹⁸O/¹⁶O and ¹³C/¹²C composition of hippopotamid enamel centred around 1.5-2.5 Ma to maximum aridity and/or maximum hydrological isolation of the rift floor from rift-external river catchment areas in response to the combined effects of rift shoulder uplift and subsidence of the rift valley floor. Structural rearrangements by ~2. 5 Ma within the northern segment of the Albertine Rift are well constrained by reversals in river flow, cannibalisation of catchments, biogeographic turnover and uplift of the Rwenzori horst. However, a growing rain shadow is not obvious in 18O/16O signatures of the hippopotamid teeth of the Albertine Rift. According to our interpretation, this is the result of the overriding effect of evaporation on 18O/16O responding to aridification of the basin floor by a valley air circulation system through relative deepening of the valley. On the other hand, a synchronous arid pulse is not so clearly recorded in palaeosol data and mammalian fauna of the eastern branch of the EARS. This discrepancy indicates that rift mesoclimates may represent an underestimated aspect in previous palaeoclimate reconstructions from rift valley data and represent a clear limitation to attempts at global climate reconstructions. The results of this study also suggest that using 18O/16O data as a proxy to rain shadow evolution must take into account relative basin subsidence to properly document mountain range uplift.13 page(s

ODP Leg 133 Northeast Australian Margin: A chronicle of carbonate platform development

Since the 1950s, modern shallow-water environments in subtropical to tropical regions that are actively producing carbonate sediments, the building material for carbonate platforms, have been choice research areas for carbonate sedimentologists. These carbonate factories serve as modern analogs for ancient carbonate environments, but knowledge of the processes controlling evolution of carbonate platforms, from their initiation through growth and demise, remains rudimentary. Understanding these processes is crucial for our interpretation of the rock record in ancient carbonate platforms

Quantitative single-molecule localization microscopy combined with rule-based modeling reveals ligand-induced TNF-R1 reorganization toward higher-order oligomers

We report on the assembly of tumor necrosis factor receptor 1 (TNF-R1) prior to ligand activation and its ligand-induced reorganization at the cell membrane. We apply single-molecule localization microscopy to obtain quantitative information on receptor cluster sizes and copy numbers. Our data suggest a dimeric pre-assembly of TNF-R1, as well as receptor reorganization toward higher oligomeric states with stable populations comprising three to six TNF-R1. Our experimental results directly serve as input parameters for computational modeling of the ligand-receptor interaction. Simulations corroborate the experimental finding of higher-order oligomeric states. This work is a first demonstration how quantitative, super-resolution and advanced microscopy can be used for systems biology approaches at the single-molecule and single-cell level