Stommel’s box model of thermohaline circulation revisited - the role of mechanical energy supporting mixing and the wind-driven gyration

Author Posting. © American Meteorological Society, 2008. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 38 (2008): 909–917, doi:10.1175/2007JPO3535.1.The classical two-box model of Stommel is extended in two directions: replacing the buoyancy constraint with an energy constraint and including the wind-driven gyre. Stommel postulated a buoyancy constraint for the thermohaline circulation, and his basic idea has evolved into the dominating theory of thermohaline circulation; however, recently, it is argued that the thermohaline circulation is maintained by mechanical energy from wind stress and tides. The major difference between these two types of models is the bifurcation structure: the Stommel-like model has two thermal modes (one stable and another one unstable) and one stable haline mode, whereas the energy-constraint model has one stable thermal mode and two saline modes (one stable and another one unstable). Adding the wind-driven gyre changes the threshold value of thermohaline bifurcation greatly; thus, the inclusion of the wind-driven gyre is a vital step in completely modeling the physical processes related to thermohaline circulation.YPG was supported by the National Science Foundation of China (NSFC, 40676022), the National Basic Research Program of China (2006CB403605), and the Guangdong Natural Science Foundation (5003672). RXH was supported by the National Oceanic and Atmospheric Administration through CICOR Cooperative Agreement NA17RJ1223 to the Woods Hole Oceanographic Institution

Light-Driven Spatiotemporal Pickering Emulsion Droplet Manipulation Enabled by Plasmonic Hybrid Microgels

The past decades have witnessed the development of various stimuli-responsive materials with tailored functionalities, enabling droplet manipulation through external force fields. Among different strategies, light exhibits excellent flexibility for contactless control of droplets, particularly in three-dimensional space. Here, we present a facile synthesis of plasmonic hybrid microgels based on the electrostatic heterocoagulation between cationic microgels and anionic Au nanoparticles. The hybrid microgels are effective stabilizers of oil-in-water Pickering emulsions. In addition, the laser irradiation on Au nanoparticles creats a “cascade effect” to thermally responsive microgels, which triggers a change in microgel wettability, resulting in microgel desorption and emulsion destabilization. More importantly, the localized heating generated by a focused laser induces the generation of a vapor bubble inside oil droplets, leading to the formation of a novel air-in-oil-in-water (A/O/W) emulsion. These A/O/W droplets are able to mimic natural microswimmers in an aqueous environment by tracking the motion of a laser spot, thus achieving on-demand droplet merging and chemical communication between isolated droplets. Such proposed systems are expected to extend the applications of microgel-stabilized Pickering emulsions for substance transport, programmed release and controlled catalytic reactions

Existence of Monotone Positive Solution of Neutral Partial Difference Equation

AbstractThis paper is concerned with a class of neutral partial difference equations. The conditions for the existence of monotone eventually positive solutions are established which improve and extend some of the criteria existing in the literature. Comparison theorems are also derived. Results are obtained on the existence of a monotone eventually positive solution of dual equation

Transcriptomic analysis of RDX and TNT interactive sublethal effects in the earthworm Eisenia fetida

<p>Abstract</p> <p>Background</p> <p>Explosive compounds such as TNT and RDX are recalcitrant contaminants often found co-existing in the environment. In order to understand the joint effects of TNT and RDX on earthworms, an important ecological and bioindicator species at the molecular level, we sampled worms (<it>Eisenia fetida</it>) exposed singly or jointly to TNT (50 mg/kg soil) and RDX (30 mg/kg soil) for 28 days and profiled gene expression in an interwoven loop designed microarray experiment using a 4k-cDNA array. Lethality, growth and reproductive endpoints were measured.</p> <p>Results</p> <p>Sublethal doses of TNT and RDX had no significant effects on the survival and growth of earthworms, but significantly reduced cocoon and juvenile counts. The mixture exhibited more pronounced reproductive toxicity than each single compound, suggesting an additive interaction between the two compounds. In comparison with the controls, we identified 321 differentially expressed transcripts in TNT treated worms, 32 in RDX treated worms, and only 6 in mixture treated worms. Of the 329 unique differentially expressed transcripts, 294 were affected only by TNT, 24 were common to both TNT and RDX treatments, and 3 were common to all treatments. The reduced effects on gene expression in the mixture exposure suggest that RDX might interact in an antagonistic manner with TNT at the gene expression level. The disagreement between gene expression and reproduction results may be attributed to sampling time, absence of known reproduction-related genes, and lack of functional information for many differentially expressed transcripts. A gene potentially related to reproduction (echinonectin) was significantly depressed in TNT or RDX exposed worms and may be linked to reduced fecundity.</p> <p>Conclusions</p> <p>Sublethal doses of TNT and RDX affected many biological pathways from innate immune response to oogenesis, leading to reduced reproduction without affecting survival and growth. A complex interaction between mixtures of RDX and TNT was observed at the gene expression level that requires further study of the dynamics of gene expression and reproductive activities in <it>E. fetida</it>. These efforts will be essential to gain an understanding of the additive reproductive toxicity between RDX and TNT.</p

Cloning, Analysis and Functional Annotation of Expressed Sequence Tags from the Earthworm \u3ci\u3eEisenia fetida\u3c/i\u3e

Background Eisenia fetida, commonly known as red wiggler or compost worm, belongs to the Lumbricidae family of the Annelida phylum. Little is known about its genome sequence although it has been extensively used as a test organism in terrestrial ecotoxicology. In order to understand its gene expression response to environmental contaminants, we cloned 4032 cDNAs or expressed sequence tags (ESTs) from two E. fetida libraries enriched with genes responsive to ten ordnance related compounds using suppressive subtractive hybridization-PCR. Results A total of 3144 good quality ESTs (GenBank dbEST accession number EH669363–EH672369 and EL515444–EL515580) were obtained from the raw clone sequences after cleaning. Clustering analysis yielded 2231 unique sequences including 448 contigs (from 1361 ESTs) and 1783 singletons. Comparative genomic analysis showed that 743 or 33% of the unique sequences shared high similarity with existing genes in the GenBank nr database. Provisional function annotation assigned 830 Gene Ontology terms to 517 unique sequences based on their homology with the annotated genomes of four model organisms Drosophila melanogaster, Mus musculus, Saccharomyces cerevisiae, and Caenorhabditis elegans. Seven percent of the unique sequences were further mapped to 99 Kyoto Encyclopedia of Genes and Genomes pathways based on their matching Enzyme Commission numbers. All the information is stored and retrievable at a highly performed, web-based and user-friendly relational database called EST model database or ESTMD version 2. Conclusion The ESTMD containing the sequence and annotation information of 4032 E. fetida ESTs is publicly accessible at http://mcbc.usm.edu/estmd

Cloning, analysis and functional annotation of expressed sequence tags from the Earthworm Eisenia fetida

<p>Abstract</p> <p>Background</p> <p><it>Eisenia fetida</it>, commonly known as red wiggler or compost worm, belongs to the Lumbricidae family of the Annelida phylum. Little is known about its genome sequence although it has been extensively used as a test organism in terrestrial ecotoxicology. In order to understand its gene expression response to environmental contaminants, we cloned 4032 cDNAs or expressed sequence tags (ESTs) from two <it>E. fetida </it>libraries enriched with genes responsive to ten ordnance related compounds using suppressive subtractive hybridization-PCR.</p> <p>Results</p> <p>A total of 3144 good quality ESTs (GenBank dbEST accession number <ext-link ext-link-type="gen" ext-link-id="EH669363">EH669363</ext-link>–<ext-link ext-link-type="gen" ext-link-id="EH672369">EH672369</ext-link> and <ext-link ext-link-type="gen" ext-link-id="EL515444">EL515444</ext-link>–<ext-link ext-link-type="gen" ext-link-id="EL515580">EL515580</ext-link>) were obtained from the raw clone sequences after cleaning. Clustering analysis yielded 2231 unique sequences including 448 contigs (from 1361 ESTs) and 1783 singletons. Comparative genomic analysis showed that 743 or 33% of the unique sequences shared high similarity with existing genes in the GenBank nr database. Provisional function annotation assigned 830 Gene Ontology terms to 517 unique sequences based on their homology with the annotated genomes of four model organisms <it>Drosophila melanogaster</it>, <it>Mus musculus</it>, <it>Saccharomyces cerevisiae</it>, and <it>Caenorhabditis elegans</it>. Seven percent of the unique sequences were further mapped to 99 Kyoto Encyclopedia of Genes and Genomes pathways based on their matching Enzyme Commission numbers. All the information is stored and retrievable at a highly performed, web-based and user-friendly relational database called EST model database or ESTMD version 2.</p> <p>Conclusion</p> <p>The ESTMD containing the sequence and annotation information of 4032 <it>E. fetida </it>ESTs is publicly accessible at <url>http://mcbc.usm.edu/estmd/</url>.</p

Leader-following consensus for high-order stochastic multi-agent systems via dynamic output feedback control

This paper studies the leader-following consensus problem for high-order stochastic nonlinear multi-agent systems. Each agent is in the strict feedback form with nonlinear functions in drift and diffusion terms and admitting time-varying incremental rates. A novel distributed observer-type consensus protocol is proposed based only on the relative output measurements of neighboring agents. The dynamic gains in controller are designed to compensate for the time-varying coefficients of nonlinear functions. By using appropriate state transformation, it is proved that the 1th moment exponential leader-following consensus is guaranteed by the proposed protocol. Different from some existing approaches, the proposed method only requires the output information of neighboring agents to be shared and does not need the observers’ full state variables to be transmitted, thus the network bandwidth is saved. In addition, the controller is constructed without using the traditional backstepping method, which makes the design procedure simple and convenient for use. Finally, a simulation example is given to illustrate the effectiveness of the theoretical results

Recent advances on the synthesis, structure, and properties of polyoxotantalates

Polyoxotantalates (POTas) are an important branch of polyoxometalates (POMs) that remain largely undeveloped compared with other members of the POM family including polyoxovanadates, polyoxotungstates, polyoxomolybdates, and polyoxoniobates. Owing to their promising applications in diverse fields such as photo/electrocatalysis, ion conduction, environmental protection, and magnetism, the development of synthetic strategies for new POTas has attracted continuous interest over the past decades. This review summarizes the current status in the development of POTas, including their synthetic methods, crystal structures, physicochemical properties, and potential applications. Additionally, synthetic challenges and prospects are also discussed. It is hoped that this review will be of reference value for the further development of POTas