scholarly journals Acoustic scattering by marine sediments with irregularities of different types

1995 ◽  
Vol 97 (5) ◽  
pp. 3387-3387
Author(s):  
Anatoliy N. Ivakin
Keyword(s):  
Marine Sediments ◽  
Acoustic Scattering ◽  
Different Types

scholarly journals Modelling acoustic scattering, sound speed, and attenuation in gassy soft marine sediments

2016 ◽  
Vol 140 (1) ◽  
pp. 274-282 ◽  
Author(s):  
A. Mantouka ◽  
H. Dogan ◽  
P. R. White ◽  
T. G. Leighton
Keyword(s):  
Marine Sediments ◽  
Sound Speed ◽  
Acoustic Scattering

Experimental Investigation of Acoustic Scattering and Reflection of Marine Sediments by the High-Speed Visualization Method

2001 ◽  
Vol 40 (Part 1, No. 5B) ◽  
pp. 3782-3783 ◽  
Author(s):  
Naotaka Koide ◽  
Laurent Derbesse ◽  
Philippe Pernod ◽  
Takahiko Otani
Keyword(s):  
Experimental Investigation ◽  
Marine Sediments ◽  
High Speed ◽  
Acoustic Scattering ◽  
Visualization Method

scholarly journals Proposal for an initial screening method for identifying microplastics in marine sediments

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Toshiro Hata ◽  
Ningjun Jiang
Keyword(s):  
Marine Sediments ◽  
Negative Impact ◽  
Screening Method ◽  
Marine Debris ◽  
Initial Screening ◽  
Testing Methods ◽  
Alternative Approach ◽  
Different Types ◽  
Sieving Process ◽  
Geotechnical Testing

AbstractMarine debris, which is often called microplastics, is widespread in marine environments, particularly in sediments, and is recognized as an environmental hazard because it concentrates contaminants, forms biofilms, and sinks into marine sediments. In sediments, it may be ingested by benthos and have a negative impact on higher food chain levels. In this study, a new protocol was developed to identify microplastics in various sediment fractions. This protocol combined sieving and staining based on ordinal geotechnical/geological testing methods. The sieving process was derived from the conventional particle size distribution test, and nontoxic dyes were employed in the staining process. The protocol is safe and easy to perform as it merely involves the use of conventional geological/geotechnical testing equipment. The new protocol was successfully employed to stain and categorize different types and sizes of microplastic particles from contaminated sediments. This safe, easy-to-use, and efficient protocol can serve as the basis for a new alternative approach to study microplastics present in sediments, which can be performed using basic materials familiar to geotechnical/geological engineers.

The extinction time of a general birth and death process with catastrophes

1986 ◽  
Vol 23 (04) ◽  
pp. 851-858 ◽  
Author(s):  
P. J. Brockwell
Keyword(s):  
Laplace Transform ◽  
Size Distribution ◽  
Sufficient Conditions ◽  
Necessary And Sufficient Conditions ◽  
Death Process ◽  
Extinction Time ◽  
Birth And Death Process ◽  
Different Types ◽  
The Laplace Transform ◽  
Necessary And Sufficient

The Laplace transform of the extinction time is determined for a general birth and death process with arbitrary catastrophe rate and catastrophe size distribution. It is assumed only that the birth rates satisfyλ0= 0,λj> 0 for eachj> 0, and. Necessary and sufficient conditions for certain extinction of the population are derived. The results are applied to the linear birth and death process (λj=jλ, µj=jμ) with catastrophes of several different types.

Differentiating between different forms of moral obligations

2020 ◽  
Vol 43 ◽  
Author(s):  
Rajen A. Anderson ◽  
Benjamin C. Ruisch ◽  
David A. Pizarro
Keyword(s):  
Moral Character ◽  
Moral Obligations ◽  
Different Types

Abstract We argue that Tomasello's account overlooks important psychological distinctions between how humans judge different types of moral obligations, such as prescriptive obligations (i.e., what one should do) and proscriptive obligations (i.e., what one should not do). Specifically, evaluating these different types of obligations rests on different psychological inputs and has distinct downstream consequences for judgments of moral character.

Ultrastructural Investigations of the Contractile Filaments of Amoebae

1974 ◽  
Vol 32 ◽  
pp. 188-189
Author(s):  
P.L. Moore
Keyword(s):  
Cytoplasmic Streaming ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Amoeboid Movement ◽  
Different Types ◽  
Chemical Conditions ◽  
Complete Interpretation

Previous freeze fracture results on the intact giant, amoeba Chaos carolinensis indicated the presence of a fibrillar arrangement of filaments within the cytoplasm. A complete interpretation of the three dimensional ultrastructure of these structures, and their possible role in amoeboid movement was not possible, since comparable results could not be obtained with conventional fixation of intact amoebae. Progress in interpreting the freeze fracture images of amoebae required a more thorough understanding of the different types of filaments present in amoebae, and of the ways in which they could be organized while remaining functional.The recent development of a calcium sensitive, demembranated, amoeboid model of Chaos carolinensis has made it possible to achieve a better understanding of such functional arrangements of amoeboid filaments. In these models the motility of demembranated cytoplasm can be controlled in vitro, and the chemical conditions necessary for contractility, and cytoplasmic streaming can be investigated. It is clear from these studies that “fibrils” exist in amoeboid models, and that they are capable of contracting along their length under conditions similar to those which cause contraction in vertebrate muscles.

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