scholarly journals Spatial Heterogeneity and Imperfect Mixing in Chemical Reactions: Visualization of Density-Driven Pattern Formation

2009 ◽  
Vol 2009 ◽  
pp. 1-4 ◽  
Author(s):  
Sabrina G. Sobel ◽  
Harold M. Hastings ◽  
Matthew Testa
Keyword(s):  
Pattern Formation ◽  
Salt Water ◽  
Model System ◽  
Reaction Vessel ◽  
Chemical System ◽  
Industrial Processes ◽  
History Of ◽  
Convection Rolls ◽  
Belousov Zhabotinsky Reaction ◽  
Complex Ion

Imperfect mixing is a concern in industrial processes, everyday processes (mixing paint, bread machines), and in understanding salt water-fresh water mixing in ecosystems. The effects of imperfect mixing become evident in the unstirred ferroin-catalyzed Belousov-Zhabotinsky reaction, the prototype for chemical pattern formation. Over time, waves of oxidation (high ferriin concentration, blue) propagate into a background of low ferriin concentration (red); their structure reflects in part the history of mixing in the reaction vessel. However, it may be difficult to separate mixing effects from reaction effects. We describe a simpler model system for visualizing density-driven pattern formation in an essentially unmixed chemical system: the reaction of pale yellow Fe3+ with colorless SCN− to form the blood-red Fe(SCN)2+ complex ion in aqueous solution. Careful addition of one drop of Fe(NO3)3 to KSCN yields striped patterns after several minutes. The patterns appear reminiscent of Rayleigh-Taylor instabilities and convection rolls, arguing that pattern formation is caused by density-driven mixing.

Turing Pattern Formation by the CIMA Reaction in a Chemical System Consisting of Quaternary Alkyl Ammonium Cationic Groups

2011 ◽  
Vol 115 (14) ◽  
pp. 3959-3963 ◽  
Author(s):  
Kouichi Asakura ◽  
Ryo Konishi ◽  
Tomomi Nakatani ◽  
Takaya Nakano ◽  
Masazumi Kamata
Keyword(s):  
Pattern Formation ◽  
Chemical System ◽  
Turing Pattern ◽  
Alkyl Ammonium ◽  
Cima Reaction

scholarly journals Comparative approaches to the study of physiology: Drosophila as a physiological tool

2013 ◽  
Vol 304 (3) ◽  
pp. R177-R188 ◽  
Author(s):  
Wendi S. Neckameyer ◽  
Kathryn J. Argue
Keyword(s):  
Gene Expression ◽  
Drosophila Melanogaster ◽  
Pattern Formation ◽  
Signaling Pathways ◽  
Human Disease ◽  
Cognitive Disorders ◽  
Model System ◽  
Critical Questions ◽  
Developmental Signaling ◽  
Shed Light

Numerous studies have detailed the extensive conservation of developmental signaling pathways between the model system, Drosophila melanogaster, and mammalian models, but researchers have also profited from the unique and highly tractable genetic tools available in this system to address critical questions in physiology. In this review, we have described contributions that Drosophila researchers have made to mathematical dynamics of pattern formation, cardiac pathologies, the way in which pain circuits are integrated to elicit responses from sensation, as well as the ways in which gene expression can modulate diverse behaviors and shed light on human cognitive disorders. The broad and diverse array of contributions from Drosophila underscore its translational relevance to modeling human disease.

scholarly journals Microbe Profile: Dictyostelium discoideum: model system for development, chemotaxis and biomedical research

Microbiology ◽  
2021 ◽  
Author(s):  
Catherine J. Pears ◽  
Julian D. Gross
Keyword(s):  
Pattern Formation ◽  
Cell Motility ◽  
Dictyostelium Discoideum ◽  
Biomedical Research ◽  
Model System ◽  
Developmental Pattern ◽  
Social Amoeba ◽  
The Social ◽  
Host Pathogen ◽  
Soil Amoeba

The social amoeba Dictyostelium discoideum is a versatile organism that is unusual in alternating between single-celled and multi-celled forms. It possesses highly-developed systems for cell motility and chemotaxis, phagocytosis, and developmental pattern formation. As a soil amoeba growing on microorganisms, it is exposed to many potential pathogens; it thus provides fruitful ways of investigating host-pathogen interactions and is emerging as an influential model for biomedical research.

scholarly journals Mechanism of Trees / Bushes Like Pattern in Chemical System

2009 ◽  
Vol 6 (3) ◽  
pp. 819-829
Author(s):  
P. K. Srivastava ◽  
Narendra Yadav
Keyword(s):  
Pattern Formation ◽  
Ir Spectra ◽  
Succinic Acid ◽  
Ammonium Sulphate ◽  
Cyclic Compound ◽  
Chemical System ◽  
Powder Spectrum ◽  
Initial Concentration ◽  
X Ray ◽  
Type Pattern

Trees / bushes like pattern have been investigated in succinic acid + ethylacetoacetate + BrO3−+ Fe (phen)3+2+ Ce+4+ H2SO4system at 30 °C in a petridish after 6 hours. These patterns are dependent on initial concentration of reactants and temperature. The system first shows fast appearing / disappearing blue and red pattern then bifurcate into concentric waves and finally shows a tree / bushes type pattern which grows in length and breadth against time. Microphotographs of trees / bushes pattern, succinic acid and ceric ammonium sulphate shows that a new compound has been formed which is responsible for this pattern. It is further confirmed by X-ray powder spectrum of trees / bushes pattern material and succinic acid. IR spectra of pattern material show that presence of cyclic compound in which Ce+4ion coordinated by hydroxyethylacetoacetate. A tentative mechanism of pattern formation is proposed.

Holkham Salts Hole, an Isolated Salt-Water pond with Relict Features. An Account Based on Studies by the late C. F. A. Pantin

1971 ◽  
Vol 51 (3) ◽  
pp. 717-741 ◽  
Author(s):  
O. D. Hunt
Keyword(s):  
Salt Marshes ◽  
Sea Water ◽  
Salt Water ◽  
High Water ◽  
North Coast ◽  
Marine Fauna ◽  
The North ◽  
Short Period ◽  
History Of ◽  
Water Pond

A saline pond known as the ‘Salts Hole’ at Holkham on the north coast of Norfolk is situated between the pine-covered sand-hills and the fields that have been reclaimed for agriculture from pre-existing salt-marshes. It has a salinity of about 75% of that of sea water and supports a peculiar relict marine fauna. Except for the rare occurrence of flooding for a short period, as in the great storm of 1953, the pond has probably been cut off from the sea for about 250 years. It presents three problems: how it got its fauna and flora; how its marine character is maintained; and how the pond originated geographically. The fauna and flora, as described, show the pond as a refuge where various marine and brackish species have managed to maintain themselves and co-exist in water outside their normal and differing ranges of salinity. The main character of the pond is kept remarkably constant with respect to salinity, alkalinity, temperature and oxygenation. The pond is a study in ‘natural engineering’, constituting a natural marine aquarium with natural controls. It is fed near the level of high-water neap tide by continuous flow from a salt spring of very constant salinity supplied from water contained in the extensive coastal sands. Its only apparent artificial feature is the outlet controlled by a dam through a culvert into a ditch that conveys its water through the fields to the sea at Wells nearly two miles away. Search in the muniment room at Holkham Hall brought to light maps dating back to Elizabethan days which show the history of the Salts Hole.

THE DISCOVERY HISTORY OF THE UNIVERSITY OIL FIELD, EAST BATON ROUGE PARISH, LOUISIANA

Geophysics ◽  
1948 ◽  
Vol 13 (3) ◽  
pp. 371-386
Author(s):  
Gordon Atwater
Keyword(s):  
Oil And Gas ◽  
Salt Water ◽  
Oil Field ◽  
State University ◽  
East Baton Rouge Parish ◽  
Louisiana State University ◽  
Shallow Wells ◽  
History Of ◽  
History Of The University ◽  
The University

The localized occurrence of salt water in shallow wells on and near the Louisiana State University campus, in addition to shells collected during the drilling of these wells, attracted the attention of geologists to this area prior to 1926. A torsion balance survey in 1931 was followed by a dry hole drilled in 1933 southeast of the present field. Three separate reflection seismograph surveys during the period of 1934 to 1937, on each one of which a well was drilled without establishing production, were made on the University structure prior to discovery in 1938. The location based on the first reflection seismograph survey should have resulted in the discovery of both the shallow and deep production, and the discovery location was finally made because of the oil and gas shows encountered in this abandoned test. After discovery, an additional reflection survey was made to detail the structure as an aid in development.

Evolutionary history of threespine sticklebacks (Gasterosteus spp.) in British Columbia: insights from a physiological clock

1995 ◽  
Vol 73 (11) ◽  
pp. 2154-2158 ◽  
Author(s):  
Rees Kassen ◽  
Dolph Schluter ◽  
John Donald McPhail
Keyword(s):  
British Columbia ◽  
Fresh Water ◽  
Evolutionary History ◽  
Egg Size ◽  
Gasterosteus Aculeatus ◽  
Salt Water ◽  
Freshwater Invasion ◽  
Freshwater Population ◽  
Threespine Sticklebacks ◽  
History Of

Geologic and allozyme evidence suggests that threespine sticklebacks (Gasterosteus aculeatus complex) in low-lying southwestern British Columbia lakes were founded during two incursions of marine sticklebacks after the retreat of the Pleistocene glaciers (the double-invasion hypothesis). We used the salinity tolerance of embryos, measured as hatchability in salt water, to establish the relative order of freshwater invasion by marine sticklebacks and to test the double-invasion hypothesis. Limnetics and an anadromous population hatched nearly equivalent numbers of young in salt water as in fresh water, whereas benthics and one solitary freshwater population had low hatchability in salt water. We also found that eggs from freshwater populations were larger than those from marine populations and limnetics had smaller eggs than benthics and the solitary population. These results support the double-invasion hypothesis and suggest a trend of increasing egg size with increasing time spent in fresh water.

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