Natural Ice-Nucleating Bacteria Increase the Freezing Tolerance of the Intertidal Bivalve Geukensia demissa

Instead of avoiding freezing, freeze tolerant invertebrates actively initiate controlled ice nucleation at relatively high sub-zero temperatures in extracellular compartments. Most produce proteinaceous ice-nucleators in their hemolymph, however the intertidal bivalve mollusc Geukensia demissa lacks this ability. Instead it utilizes at least one strain of ice-nucleation active (INA) bacteria, Pseudomonas fulva, present in seawater, to induce crystallization in the pallial fluid that fills its mantle cavity. In this study, two additional INA bacteria strains were isolated from the palial fluid of Geukensia demissa: Psychrobacter sp. and Shewanella sp. The ice-nucleation activity of both strains was characterized and Psychrobacter was found to consistently induce nucleation at temperatures 1-3°C higher than Shewanella. Based on 16S rRNA sequencing, neither of these bacteria have yet been identified. The effects of Psychrobacter on the freeze tolerance of summer-acclimatized Geukensia were assessed and compared to the freeze tolerance of winter-acclimatized specimens. This assessment was accomplished through whole-organism death experiments involving 12-hour periods of exposure to sub-zero temperatures and cell viability tests using a LIVE/DEAD sperm viability kit (Molecular Probes, Inc, Eugene, OR). Adding INA bacteria to summer-acclimatized Geukensia reduced their LT50 from -12.5°C to -15.0°C. The LT50 of winter-acclimatized specimens was determined to be -16.5°C. This result may be explained by the presence of cryoprotectants and multiple strains of bacteria in the winter-acclimatized specimens. Gill cell viability tests resulted in an average of 12% greater damage in summer-acclimatized Geukensia without added bacteria at -13.5°C, but no significant differences at -10°C and -15°C. This study is, to our knowledge, the first time that a bacterium has been shown to increase the survival of a freeze tolerant animal

The Incompatibility of a Daily School Pledge with a Democratic and Multicultural Education

The Pledge of Allegiance has become a tradition in schools throughout the United States. The debate on this practice has often been limited due to the ideas of national pride that surround the pledge. This article addresses both the problematic history of the pledge, the protected precedence of teachers and students refusing to state the pledge, the pledge’s international abnormality, and the practical and philosophical concerns of a daily pledge in the public school setting. The article’s contention is that the pledge introduces a shallow view of national loyalty, while simultaneously endangering religious liberty, overlooking the views of marginalized and immigrant students, and promoting nationalism and a more subtle militarism. The article concludes with beneficial alternatives schools could use in place of a daily pledge and the societal benefits of reconsidering this tradition

Communications on Agricultural Research, Development, and Extension Teams

Domestically and internationally, agricultural research, development, and extension (ARD&E) programs are experiencing a resurgent interest in interdisciplinary collaboration as a more effective approach to enhancing farm productivity and human well-being

Anomalies in the carbonate system of Red Sea coastal habitats

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Baldry, K., Saderne, V., McCorkle, D. C., Churchill, J. H., Agust, S., & Duarte, C. M. Anomalies in the carbonate system of Red Sea coastal habitats. Biogeosciences, 17(2), (2020): 423-439, doi:10.5194/bg-17-423-2020.We use observations of dissolved inorganic carbon (DIC) and total alkalinity (TA) to assess the impact of ecosystem metabolic processes on coastal waters of the eastern Red Sea. A simple, single-end-member mixing model is used to account for the influence of mixing with offshore waters and evaporation–precipitation and to model ecosystem-driven perturbations on the carbonate system chemistry of coral reefs, seagrass meadows and mangrove forests. We find that (1) along-shelf changes in TA and DIC exhibit strong linear relationships that are consistent with basin-scale net calcium carbonate precipitation; (2) ecosystem-driven changes in TA and DIC are larger than offshore variations in >70 % of sampled seagrass meadows and mangrove forests, changes which are influenced by a combination of longer water residence times and community metabolic rates; and (3) the sampled mangrove forests show strong and consistent contributions from both organic respiration and other sedimentary processes (carbonate dissolution and secondary redox processes), while seagrass meadows display more variability in the relative contributions of photosynthesis and other sedimentary processes (carbonate precipitation and oxidative processes). The results of this study highlight the importance of resolving the influences of water residence times, mixing and upstream habitats on mediating the carbonate system and coastal air–sea carbon dioxide fluxes over coastal habitats in the Red Sea.This research has been supported by the King Abdullah University of Science and Technology (KAUST) (grant nos. BAS/1/1071-01-01 and BAS/1/1072-01-01) and the Investment in Science fund at WHOI

The Friedel-Crafts Reaction with Furans

2-Furoic acid, aluminum chloride and substituted benzenes give 6-substituted-l-naphthoic acids. For example, with chlorobenzene the product is 6-chloro-1-naphthoic acid; with anisole, 6-methoxy-1-naphthoic acid; with toluene, 6-methyl-1-naphthoic acid

Interactive Design Using CFD and Virtual Engineering

Virtual engineering is a powerful concept, defined as a technology that integrates geometric models and related engineering tools such as analysis and simulation, optimization and decision-making tools, etc. within a computer generated environment that facilitates multidisciplinary and collaborative product realization [1]. Virtual engineering applications can be constructed from scratch with high-level programming languages. However, since the end-user of the virtual engineering application is most likely not a programming expert, high-level support is needed to provide the user with the capability to construct his own application in an intuitive manner and with minimal coding. In this paper, we present a framework of the virtual engineering environment and its implementation, identify the general requirements for a virtual engineering application, and summarize the architecture. A virtual engineering application on computational fluid dynamics (CFD)-based interactive design is used to motivate the research as well as to evaluate the performance of the system. The sample application is related to the coal transport system of a coal-fired power plant. Finally, the topics for future research are given

Globalization and the Chinese Knowledge Diaspora: An Australian Case Study

In a context of intensified globalisation, knowledge diaspora as “trans-national human capital” have become increasingly valuable to society. With an awareness of a need for more empirical studies especially in Australia, this article concentrates on a group of academics who were working at a major university in Australia and came originally from the Chinese mainland. The study explores their life, work and international research collaborations, using a case study approach with semi-structured interviews as the data collection method. The study found that while globalisation shapes the work and the contributions to Australia, by academics from China, they exert their initiatives to respond to and further reshape globalisation. Equipped with their Chinese cultural and educational backgrounds, academic experience in the West, and active membership in the international knowledge system, the Chinese knowledge diaspora are a modern kind of cosmopolitan literati. They are aware of the impact of globalisation and contribute actively to higher education internationalisation in both Australia and China, have maintained their cultural identity and made good use of their Chinese educational background. Their international collaborations, however, are more likely to be with the scholars from Western countries due to some difficulties they have experienced in China and Australia, and to the current setup of the global knowledge system.postprin