35,933 research outputs found
Antisolvent gibbsite crystallisation from synthetic Bayer liquor
No full textIncludes bibliographical references (leaves 45-49).The current Bayer precipitation of gibbsite is notoriously slow and is considered to be the rate limiting step of the Bayer process. The present industrial reactor configuration involves precipitating gibbsite inside a series of large stainless steel agitated vessels due to the slow precipitation kinetics of gibbsite from pregnant Bayer liquor. The scope of this study is to investigate the effectiveness of using water as an antisolvent to increase the overall gibbsite yield and the associated particle behaviours under isothermal conditions. The experiments were performed in a series of batch experiments which were divided into two subsets. Firstly, the effect of different caustic concentrations present in the anti solvent on gibbsite yield was tested. Secondly, the effect of different seed loading (50 and 100 grams seeds per liter of synthetic liquor) on aggregation and fines formation were investigated. All batch experiments were conducted isothermally at 80°C under a closed system using a baffled stainless steel 316 agitated vessel. The experimental results indicated water to be a feasible medium for the isothermal antisolvent crystallisation of gibbsite from synthetic pregnant Bayer liquor. It was found that the extent of overall gibbsite yield exhibits a power law correlation to the change in the antisolvent caustic concentration with R2 ～1 (R2 = 0.99974). This finding is important as the regressed curve will be used to correlate gibbsite yield as a function of anti solvent purity. From the seed loading experiments, an Increase In seed loading under constant temperature and initial liquor supersaturation resulted in an overall decrease in product particle size due to a rise in inter-particulate attrition. However, crystal growth was not dominant during any period of the experiments with aggregation being more prominent for the system with the lower seed load. Gibbsite morphology determination from SEM revealed hexagonal solids which, in the presence of a higher seed loading indicated signs of fracture due to attrition. Quantitative evidence of this mechanism is shown USIng the discretised population balance method by Bramley et al. (1996) with the aid of the computational technique developed by Hounslow (2005) in Mathematica. Results generated using this method show decreasing aggregation with liquor de supersaturation and increased seed loading. The overall particle behaviours from the current investigation are validated by results obtained from previous gibbsite studies under very similar conditions. Although the gibbsite yield can be increased drastically in the presence of an anti solvent, the average particle size generated from this study is still too small to be commercially feasible due to the increase in initial supersaturation. Thus it is recommended that further particle size optimisation may be conducted inside a fluidised bed reactor where particles generally experience lower shear than inside a conventional agitated vessel
Revision der Spinnenfamilie Psechridae (Arachnida: Araneae): Biodiversitätsforschung und Phylogenie mithilfe morphologischer und molekularer Methoden
No full textDie vorliegende, publikationsbasierte Dissertation, bestehend aus den drei Einzelpublikationen Bayer (2011, 2012) und Bayer und Schönhofer (2012), verfolgte das Ziel, die Spinnenfamilie Psechridae zu revidieren. Weiterhin sollten die phylogenetische Position dieser Familie im System der höheren Webspinnen (Araneomorphae) sowie die phylogenetischen Beziehungen der einzelnen Arten innerhalb der beiden Gattungen der Psechridae untersucht werden. In Form von morphologisch-taxonomischen Bearbeitungen wurden die beiden die Psechridae bildenden Gattungen Psechrus und Fecenia revidiert, wobei sämtliches Typus-Material sowie reichhaltiges, weiteres Material eingehend beschrieben, illustriert und diagnostiziert wurde. Hierbei wurden auch intraspezifische Variabilität sowie die Prä-Epigynen subadulter Weibchen, die in taxonomischen Arbeiten bislang nur eine unwesentliche Rolle gespielt haben, beschrieben, illustriert und taxonomisch ausgewertet. Zudem wurden im Rahmen dieser Untersuchungen bereits Überlegungen über mögliche Verwandtschaftsbeziehungen innerhalb der beiden Gattungen angestellt. ..
Systematic reviews from an epidemiological perspective - interview with Dorle Hoffmann and Oliver Bayer
No full textIn this interview, epidemiologists Dorle Hoffmann and Oliver Bayer give an insight into their experience with systematic reviews and related topics such as meta-analyses. They describe how the tasks have expanded step by step in recent years and the importance of local networking - especially with the medical library staff. Finally, the interview describes the role librarians can play in the preparation of systematic reviews and gives an insight into how the cooperation in Mainz is progressing with the development of a practical guide and joint training courses.Im vorliegenden Interview geben die Epidemiolog*innen Dorle Hoffmann und Oliver Bayer Einblick in ihre Erfahrungen mit systematischen Reviews bzw. damit verwandten Themen wie Metaanalysen. Sie beschreiben, wie sich die Aufgaben in den letzten Jahren Schritt für Schritt erweitert haben und welchen Stellenwert die Vernetzung vor Ort spielt - insbesondere mit der medizinischen Bibliothek. Zuletzt wird im Interview dargestellt, welche Rolle Bibliothekar*innen bei der Erstellung systematischer Reviews spielen können und sie geben einen Einblick, wie sich die konkrete Zusammenarbeit in Mainz mit der Entwicklung eines Praxisleitfadens und gemeinsamer Schulungsangebote gestaltet
Sclerobelemnon theseus Bayer 1959
No full text<i>Sclerobelemnon theseus</i> Bayer, 1959 <p>(Figure 48)</p> <p> <i>Sclerobelemnon theseus</i> Bayer, 1959b:33; Figs. 18–21; 1961:304; Fig. 98.— Bayer 1961:304; Fig. 98.</p> <p> <b>Material examined.</b> SERTC S 2312, 79 m, off Charleston, South Carolina, April 23, 1977.</p> <p> <b>Remarks.</b> This species has a club-like shape with the peduncle slightly longer than the rachis. The distal end of the peduncle is slightly pointed and not inflated to any extent. The examined specimen is about 7 mm at its widest point and 65 mm in length. The rachis contains some exsert autozooids but most are contracted, with minute, indistinct siphonoozooids scattered between polyps. The autozooids are arranged in 12 indistinct longitudinal rows, leaving a bare dorsal streak along the back of the colony. The axis is slightly flexible and the coenenchyme is tough and rubbery. The color of the colony is creamy white in alcohol.</p> <p> The autozooids contain sclerites in the form of plates that resemble double sided axe heads or plates with a medial constriction, reaching 0.3 mm in length. The ends of some plates have serrated or ridged edges. The rachis contains similar plates with a medial constriction and serrations, and the peduncle contains smaller plate-like bodies. This is the first record of this species in the SAB, although one specimen in the USNM from Cape Fear is identified as <i>Sclerobelemnon</i> sp. and was not examined for this work.</p> <p> <b>Atlantic distribution:</b> Charleston, 79 m, Gulf of Mexico (unknown depth), Surinam, Trinidad, 57 m (Bayer 1959b; Bayer 1961; Williams 1995; NMNH collections; SERTC collection).</p>Published as part of <i>Devictor, Susan T. & Morton, Steve L., 2010, Identification guide to the shallow water (0 - 200 m) octocorals of the South Atlantic Bight 2599, pp. 1-62 in Zootaxa 2599 (1)</i> on page 55, DOI: 10.11646/zootaxa.2599.1.1, <a href="http://zenodo.org/record/10095192">http://zenodo.org/record/10095192</a>
Single- and Multi-carrier Quadrature Amplitude Modulation: Principles and Applications for Personal Communications, WATM and Broadcasting: 2nd
No full textSingle- and Multi-carrier Quadrature Amplitude Modulation Principles and Applications for Personal Communications, WLANs and Broadcasting L. Hanzo Department of Electronics and Computer Science, University of Southampton, UK W. Webb Motorola, Arlington Heights, USA formerly at Multiple Access Communications Ltd, Southampton, UK T. Keller Ubinetics, Cambridge Technology Centre, Melbourn, UK formerly at Department of Electronics and Computer Science, University of Southampton, UK Motivated by the rapid evolution of wireless communication systems, this expanded second edition provides an overview of most major single- and multi-carrier Quadrature Amplitude Modulation (QAM) techniques commencing with simple QAM schemes for the uninitiated through to complex, rapidly-evolving areas, such as arrangements for wide-band mobile channels. Targeted at the more advanced reader, the multi-carrier modulation based second half of the book presents a research-orientated outlook using a variety of novel QAM-based arrangements. * Features six new chapters dealing with the complexities of multi-carrier modulation which has found applications ranging from Wireless Local Area Networks (WLAN) to Digital Video Broadcasting (DVB) * Provides a rudimentary introduction for readers requiring a background in the field of modulation and radio wave propagation * Discusses classic QAM transmission issues relevant to Gaussian channels * Examines QAM-based transmissions over mobile radio channels * Incorporates QAM-related orthogonal techniques, considers the spectral efficiency of QAM in cellular frequency re-use structures and presents a QAM-based speech communications system design study * Introduces Orthogonal Frequency Division Multiplexing (OFDM) over both Gaussian and wideband fading channels By providing an all-encompassing self-contained treatment of single- and multi- carrier QAM based communications, a wide range of readers including senior undergraduate and postgraduate students, practising engineers and researchers alike will all find the coverage of this book attractive
Telemedicine in Alentejo.
No full text08.01.14 KB. Ok to add published version to spiral, Sherpa Romeo.Abstract Alentejo covers a third of Portugal, yet it is home to only 5% of the population. Residents of the region are poorer, older, and less educated than the rest of the country. There is a shortage of physicians in several specialties. The low population density, a concentration of specialized services, and a poor public transportation network all create barriers to access. Telemedicine was introduced in 1998 to help address these challenges. In this article, we provide an overview of the program and its current status, focusing on infrastructure, services, and activity volume. We also discuss the impact the program has had from the perspectives of patients and healthcare professionals. From 1998 to 2011, there were 132,546 episodes of service using telemedicine, including real-time teleconsultations, teleradiology, teleultrasound, and telepathology. At present, the network includes 20 primary care units and five hospitals, covering almost 30,000 km(2) and 500,000 people. Units have high-resolution videoconferencing equipment, access to patients' clinical records, an image archive, and peripherals, such as electronic dermatoscopes and phonendoscopes. Teleconsultations are available in 15 medical specialties and areas, ranging from neurology to pediatric surgery. In 2008, regional health authorities started a tele-education program, and by the end of 2011, 876 healthcare professionals, across 52 locations, had participated in remote learning sessions. More than a decade since telemedicine was introduced in Alentejo, it is now an integral part of everyday service provision. A comprehensive assessment of the costs and consequences of the program is currently underway
Aglaoprimnoa stefanii Bayer 1996
No full textAglaoprimnoa stefanii Bayer, 1996 Material examined: BBB 2016: St. 21. Distribution: Off South Georgia (54°29’S, 39°22’W 659–686 m); Burdwood bank: (54°41’S, 56°59’W to 54°41’S, 57°03’W, 70 m; 54°39’S, 57°09’W to 54°39’S, 57°12’W, 124 m) (Bayer 1996a); Burdwood bank (785 m) (present study). Remarks: The occurrence of this species was expected, as the genus Aglaoprimnoa is monotypic and the Burdwood bank is its type locality.Published as part of Schejter, L., Genzano, G., Pérez, C. D., Acuña, F., Cordeiro, R. T. S., Silva, R. A., Garese, A. & Bremec, C. S., 2020, Checklist of Benthic Cnidaria in the SW Atlantic Ocean (54 ºS- 56 ºS), pp. 201-239 in Zootaxa 4878 (2) on page 222, DOI: 10.11646/zootaxa.4878.2.1, http://zenodo.org/record/442488
Letter from Stephen T. Mather, U.S. National Park Service to Jesse L. Boyce
No full textLetter from the Director of the National Park Service, Stephen T. Mather, to Jesse L. Boyce informing him that immediate action is being taken to remove the TNT from the Grand Canyon
DNA fusion gene vaccination mobilizes effective anti-leukemic cytotoxic T lymphocytes from a tolerized repertoire
No full textThe majority of known human tumor-associated antigens derive from non-mutated self proteins. T cell tolerance, essential to prevent autoimmunity, must therefore be cautiously circumvented to generate cytotoxic T cell responses against these targets. Our strategy uses DNA fusion vaccines to activate high levels of peptide-specific CTL. Key foreign sequences from tetanus toxin activate tolerance-breaking CD4+ T cell help. Candidate MHC class Ibinding tumor peptide sequences are fused to the C terminus for optimal processing and presentation. To model performance against a leukemia-associated antigen in a tolerized setting, we constructed a fusion vaccine encoding an immunodominant CTL epitopederived from Friend murine leukemia virus gag protein (FMuLVgag) and vaccinated tolerant FMuLVgag-transgenic (gag-Tg) mice. Vaccination with the construct induced epitopespecificIFN-c-producing CD8+ T cells in normal and gag-Tg mice. The frequency and avidity of activated cells were reduced in gag-Tg mice, and no autoimmune injury resulted. However, these CD8+ T cells did exhibit gag-specific cytotoxicity in vitro and in vivo. Also, epitope-specific CTL killed FBL-3 leukemia cells expressing endogenous FMuLVgag antigen and protected against leukemia challenge in vivo. These results demonstrate a simple strategy to engage anti-microbial T cell help to activate epitope-specific polyclonal CD8+ T cell responses from a residual tolerized repertoire
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