Lateral-line-like antennae of certain of the Penaeidea (Crustacea, Decapoda, Natantia)

1985 ◽  
Vol 226 (1244) ◽  
pp. 249-261 ◽  
Keyword(s):  
Mechanical Properties ◽  
Lateral Line ◽  
Sea Water ◽  
External Source ◽  
Rigid Bodies ◽  
The Body ◽  
Decapod Crustaceans ◽  
Lateral Lines ◽  
As If ◽  
The Way

Some pelagic decapod crustaceans have long trailing antennal ‘flagella’, the distal parts of which are heavily setosed. In these distal parts some setae form tubes known to contain mechanoreceptors and so resemble the lateral lines of many common fishes. We have studied some of the mechanical properties of these specialized flagella from animals of the families Sergestidae and Penaeidae. Both proximal and distal parts of the flagella are flexible at right angles to their lengths but behave like rigid bodies longitudinally. This means that when the animal is exposed to vibrations in the surrounding sea water the distal parts behave, at all frequencies greater than about 1 Hz, as if they are, in the planes perpendicular to the axes of the proximal parts, mechanically independent of the animal’s body. The way in which the ratio of the displacements of the mechanoreceptors in the distal parts of the flagellum and the displacements of the sea water outside the flagellum changes with frequency was found. This resembles that found for some fish lateral lines. From these results it seems that these crustaceans have two ‘lateral lines’ widely spaced from the animal’s body and mechanically independent of the body. For such a system the patterns of excitation of the mechano­receptors of the flagella will change in an even more dramatic way with change in position of an external source of vibration than will be the case for fish lateral lines. We have calculated such changes in pattern for a few simple spatial dispositions of a vibrating source and a crustacean of this kind.

Stimulation of the acoustico-lateralis system of clupeid fish by external sources and their own movements

1993 ◽  
Vol 341 (1296) ◽  
pp. 113-127 ◽  
Keyword(s):  
Lateral Line ◽  
External Source ◽  
Clupea Harengus ◽  
Pressure Gradients ◽  
Surrounding Water ◽  
Low Frequencies ◽  
Lateral Recess ◽  
Lateral Lines ◽  
External Sources ◽  
Net Pressure

1. The receptor organs of the acoustico-lateralis system in fish respond in various ways to pressures and pressure gradients and provide the fish with information about external sources of vibration. 2. A fish’s movements will set up pressures and pressure gradients and this poses three questions, (i) Can a fish obtain useful information from self-generated pressures and pressure gradients? (ii) To what extent do self-generated pressures mask signals from external sources? (iii) Can interactions between external and self-generated pressures and gradients in the acoustico-lateralis system give patterns of activity from the receptor organs which have special significance? 3. In herring ( Clupea harengus L. ) and sprat ( Spratus sprattus (L.)) measurements have been made of dimensions of various parts of the acoustico-lateralis system particularly of the subcerebral perilymph canal which crosses the head between the lateral lines. 4. Self-generated pressures produced by lateral movements of the head are antisymmetric, i.e. equal and opposite in sign on the left and right sides of the head. They oppose the accelerations of the head that produce them. In contrast, external sources give pressures that are largely symmetric. Any pressure gradients they give will accelerate the fish and the surrounding water together and any net pressure gradients will be small and so will any flows through the subcerebral perilymph canal. 5. Flows of liquid between the lateral lines across the lateral-recess membranes have been measured at various frequencies for pressure gradients applied across the head. Between 5 and 200 Hz the velocity of flow per unit pressure does not vary by more than than a factor of 2. At low frequencies the absolute values of flow are very much larger (more than 50 times) than those found for equally large symmetrically applied pressures (as from an external source) due to flow into the elastic gas containing bullae. 6. It is calculated that a net pressure difference (at optimum frequency) across the head of only 0.008 Pa will reach threshold for the lateral line neuromast nearest the lateral recess and one of 0.02 Pa for that under the eye. The responses of these neuromasts are expected to saturate and provide little information when the pressure differences across the head exceed 6 to 18 Pa. The pressures given by the swimming fish are discussed in the light of a theory advanced by Lighthill in the paper that follows this paper. With such antisymmetric pressures the direction of flow in the lateral-line canals will be towards the lateral recess on one side of the fish and away on the other and so differ from the situation found with an external source when flow at any instant will be either towards or away from the lateral recess on both sides of the head. 7. Antisymmetric pressures can produce large flows past the utricular maculae. However, at low frequencies flows across the maculae, on which their stimulation depends, will be small. We do not know the direction of these latter flows though they will be in opposite sense on the two sides of the head, again unlike the situation with an external source. 8. Calculations of impedances below 30 Hz show that the observed flows across the head are consistent with the dimensions and properties of the known structures. 9. There are major and systematic differences in the patterns of receptor organ stimulation between those expected from external sources and from a fish’s own movements. 10. Experiments on the red mullet ( Mullus surmuletus L.) showed that it too has a transverse channel connecting the right and left lateral-line systems. At low frequencies its properties resemble those of the subcerebral perilymph canal of the clupeid.

Mechanical factors in the excitation of clupeid lateral lines

1983 ◽  
Vol 218 (1210) ◽  
pp. 1-26 ◽  
Keyword(s):  
Lateral Line ◽  
Sea Water ◽  
Capillary Tube ◽  
Rigid Bodies ◽  
Clupea Harengus ◽  
Lateral Line System ◽  
Canal System ◽  
Cross Sectional ◽  
Line System ◽  
Lateral Line Canal

The excitation of lateral line sense organs (neuromasts) might be expected to depend on differences of movement between the liquid inside the main lateral line canals (the ones that contain the neuromasts) and the walls of these canals. We have investigated this net movement in relation to events in the water around fish. Liquid displacements inside a given part of a main lateral line canal of the sprat ( Sprattus sprattus (L.)) are, at any one frequency, linearly related to those in the medium (sea water) adjacent to this part. For the parts of the canal system studied, and below about 80 Hz, the ratio of displacement inside the canal to that in the medium falls with frequency, i. e. the displacement inside the canal follows the velocity in the medium. Sea water displacements in a given length of a main lateral line canal system are proportional to the component of the external velocity that is parallel to the canal. For this component the ratio of displacements inside and outside the lateral line approaches unity at around 80 Hz. The behaviour of a lateral line canal is close to that of a straight capillary tube of roughly the same cross sectional area. Displacements in the canal are advanced in phase relative to those in the external medium and these phase advances are a little larger than those found in capillaries. There is very little mechanical coupling between neighbouring parts of the main canals. Since the cupulae of the neuromasts of the sprat lateral line are driven by frictional forces, the stimulus to a neuromast will (below 80 Hz) be proportional to the acceleration of the medium adjacent to the lateral line. Sprats and fish of three other species ( Clupea harengus L., Hyperoplus lanceolatus (Lesauvage), and Trachurus trachurus (L.) have been shown, when suspended in sound fields emitted by pulsating and vibrating sources, to behave longitudinally as rigid bodies. Under many conditions it proved possible to calculate the longitudinal movements of fish from the differences of pressure between snout and tail. From these two kinds of result we have calculated for a variety of positions in fields around vibrating bodies the motion of a fish and the motion of the liquid in the canals and so estimated the effective stimulus to different parts of the lateral line system. When such calculations were made for a vibrating source of the dimensions of a sprat tail, and for distances comparable to the inter-fish distance within a school, we found that the patterns of net velocities at different neuromasts change dramatically with the position or angle of the fish relative to the source. We estimate that the sprat lateral line system excited in this way could detect a neighbouring fish in a school at distances of up to a few fish lengths. The sprat lateral line sensory system is well suited to giving sensory information in such activities as schooling.

Ionic regulation in the squat lobster Galathea squamifera, with special reference to the relationship between potassium metabolism and the accumulation of radioactive caesium

1965 ◽  
Vol 45 (1) ◽  
pp. 97-113 ◽  
Author(s):  
G. W. Bryan
Keyword(s):  
Urinary Excretion ◽  
Sea Water ◽  
The Body ◽  
Ionic Regulation ◽  
Decapod Crustaceans ◽  
High Permeability ◽  
General Study ◽  
Squat Lobster ◽  
The Relationship ◽  
Potassium Metabolism

The absorption of radioactive Cs from sea water in relation to K metabolism has been examined in the squat lobster Galathea squamifera. A general study has been made of the ability of Galathea to carry out osmotic and ionic regulation as a comparison with better known decapod crustaceans which have previously been used for radioactive Cs experiments.Galathea appears to be a truly marine decapod in that it is probably unable to osmoregulate and the body surface is very permeable to water and to Cs and Kions. Despite this high permeability, Galathea is able to regulate K and radioactive Cs at blood plasma levels which are 1.3 and 1.1 times those of sea water. The Na and Cl concentrations in the plasma are not regulated and the Ca concentration is variable, but Mg and SO4 are maintained at concentrations below those of sea water. Urinary excretion does not assist in the conservation of K or radioactive Cs in the plasma but assists in removing Mg and SO4.

scholarly journals Novel Hydrogels of Chitosan and Poly (vinyl alcohol) Reinforced with Inorganic Particles of Bioactive Glass

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 691
Author(s):  
O. Sánchez-Aguinagalde ◽  
Ainhoa Lejardi ◽  
Emilio Meaurio ◽  
Rebeca Hernández ◽  
Carmen Mijangos ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Drug Release ◽  
Bioactive Glass ◽  
Vinyl Alcohol ◽  
Release Kinetics ◽  
The Body ◽  
Poly Vinyl Alcohol ◽  
X Ray Diffraction ◽  
Inorganic Particles ◽  
Release Studies

Chitosan (CS) and poly (vinyl alcohol) (PVA) hydrogels, a polymeric system that shows a broad potential in biomedical applications, were developed. Despite the advantages they present, their mechanical properties are insufficient to support the loads that appear on the body. Thus, it was proposed to reinforce these gels with inorganic glass particles (BG) in order to improve mechanical properties and bioactivity and to see how this reinforcement affects levofloxacin drug release kinetics. Scanning electron microscopy (SEM), X-ray diffraction (XRD), swelling tests, rheology and drug release studies characterized the resulting hydrogels. The experimental results verified the bioactivity of these gels, showed an improvement of the mechanical properties and proved that the added bioactive glass does affect the release kinetics.

scholarly journals Mobilizing the Sense of “Fat”: A Phenomenological Materialist Approach

Human Studies ◽  
2021 ◽  
Author(s):  
Jenny Slatman
Keyword(s):  
Lived Experiences ◽  
Fat Body ◽  
The Body ◽  
New Materialism ◽  
Writing Style ◽  
Conceptual Frame ◽  
Fat Bodies ◽  
The Way ◽  
Phenomenological Exploration

AbstractThis paper aims to mobilize the way we think and write about fat bodies while drawing on Jean-Luc Nancy’s philosophy of the body. I introduce Nancy’s approach to the body as an addition to contemporary new materialism. His philosophy, so I argue, offers a form of materialism that allows for a phenomenological exploration of the body. As such, it can help us to understand the lived experiences of fat embodiment. Additionally, Nancy’s idea of the body in terms of a “corpus”—a collection of pieces without a unity—together with his idea of corpus-writing—fragmentary writing, without head and tail—can help us to mobilize fixed meanings of fat. To apply Nancy’s conceptual frame to a concrete manifestation of fat embodiment, I provide a reading of Roxane Gay’s memoir Hunger (2017). In my analysis, I identify how the materiality of fat engenders the meaning of embodiment, and how it shapes how a fat body can and cannot be a body. Moreover, I propose that Gay’s writing style—hesitating and circling – involves an example of corpus-writing. The corpus of corpulence that Gay has created gives voice to the precariousness of a fat body's materialization.

Influence of the mechanical stretch property of fabrics on the wear comfort of men’s suit pants

2021 ◽  
pp. 004051752110191
Author(s):  
Hiroyuki Kanai ◽  
Kentaro Ogawa ◽  
Tetsu Sasagawa ◽  
Kiyohiro Shibata
Keyword(s):  
Mechanical Properties ◽  
Pressure Measurement ◽  
Mechanical Stretch ◽  
The Body ◽  
Weft Yarn ◽  
Elongation Ratio ◽  
Weft Direction ◽  
Wear Comfort ◽  
Finishing Process ◽  
Elastic Thread

The stretch property of fabrics is one of the most important factors that provide comfort to wearers. It is expected that tension building up in the fabric can be relaxed and the garment pressure on the body can be reduced by appropriately exploiting its stretch property. Currently, the stretch property is predominantly realized using spandex. However, weaving or knitting elastic threads cannot be employed for the worsted fabric used to design men’s suits because of their effects on the mechanical properties of the fabric (e.g., embrittlement), which deteriorate with time. In this study, worsted fabric with a graded mechanical stretch property was produced, and the effect of the mechanical stretch property on comfort was verified. The mechanical stretch property is developed from the tension relaxation and fabric shrinkage along the weft yarn during the crabbing, scouring, and drying stages of the finishing process. Then, the form of the fabric is set by heating. In this study, the worsted fabric had an elongation ratio varying from 5.9% to 16.1% along the weft direction that was produced without using elastic thread. Furthermore, men’s suit pants were made from the fabrics. The effect of the stretch property on the garment comfort was verified through sensory evaluation and garment pressure measurement. The contribution of the mechanical stretch property in improving the garment comfort of men’s suit pants is discussed.

scholarly journals Injectable non-leaching tissue-mimetic bottlebrush elastomers as an advanced platform for reconstructive surgery

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Erfan Dashtimoghadam ◽  
Farahnaz Fahimipour ◽  
Andrew N. Keith ◽  
Foad Vashahi ◽  
Pavel Popryadukhin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Reconstructive Surgery ◽  
Biomedical Applications ◽  
The Body ◽  
Surrounding Tissue ◽  
Curing Time ◽  
Materials Used ◽  
Significant Health

AbstractCurrent materials used in biomedical devices do not match tissue’s mechanical properties and leach various chemicals into the body. These deficiencies pose significant health risks that are further exacerbated by invasive implantation procedures. Herein, we leverage the brush-like polymer architecture to design and administer minimally invasive injectable elastomers that cure in vivo into leachable-free implants with mechanical properties matching the surrounding tissue. This strategy allows tuning curing time from minutes to hours, which empowers a broad range of biomedical applications from rapid wound sealing to time-intensive reconstructive surgery. These injectable elastomers support in vitro cell proliferation, while also demonstrating in vivo implant integrity with a mild inflammatory response and minimal fibrotic encapsulation.

Is God Really in History?

1979 ◽  
Vol 15 (3) ◽  
pp. 379-390
Author(s):  
Frederick Sontag
Keyword(s):  
Nineteenth Century ◽  
Human Life ◽  
History Of ◽  
The Relationship ◽  
As If ◽  
The Way

For some time it seemed as if Christianity itself required us to say that ‘God is in history’. Of course, even to speak of ‘history’ is to reveal a bias for eighteenth- and nineteenth-century forms of thought. But the justification for talking about the Christian God in this way is the doctrine of the incarnation. The centre of the Christian claim is that Jesus is God's representation in history, although we need not go all the way to a full trinitarian interpretation of the relationship between God and Jesus. Thus, the issue is not so much whether God can appear or has appeared within, or entered into, human life as it is a question of what categories we use to represent this. To what degree is God related to the sphere of human events? Whatever our answer, we need periodically to re-examine the way we speak about God to be sure the forms we use have not become misleading.

Generation Z: The Purchase Intention of Green Skin Care Products

2021 ◽  
Vol 12 (1) ◽  
pp. 83-83
Author(s):  
Ying San, Lim ◽  
Phing Cai ◽  
Andy Hong ◽  
Tuan Hock, Ng ◽  
Ying Zhee, Lim
Keyword(s):  
Purchase Intention ◽  
Theory Of Planned Behaviour ◽  
Good Condition ◽  
Skin Care ◽  
The Body ◽  
Growing Up ◽  
Care Industry ◽  
Generation Z ◽  
Skin Care Products ◽  
The Way

The cosmetics and toiletry industry has growing up very fast. In 2016, the total global revenue cosmetics industry amounted to USD$444 billion. According to Lee, Goh, & Noor ( 2019), the skincare products dominated the cosmetics and toiletry market with a market value of approximately USD$ 120 billion. Between 2012 and 2019, the global skincare market expanded by 41.8 percent, and by 2025, it is expected to be worth $189 billion (Ledesma, 2020). The skin is the largest organ in the body, hence, many people will find ways to protect it, one of the way people are using to protect the skin is to apply any supplement on skin to keep the good condition of the skin. However, according to Cunningham (2014), the used of chemical items in the cosmetic skin care industry is extremely unregulated. For example, Parabens that cause breast cancer are found in cosmetics. The chemical used in the skin care products had rise the attention of the users to start to pay attention on the ingredient of the skin care products. One of the way people are using in order to avoid the harmful chemical in skin care products is to to choose skin care with natural ingredient (Espitia, 2020), this happend especially among the younger consumers (Boon et al., 2020; Hsu et al.,2017). The green skincare industry is growing rapidly. Green skin care, according to previous studies (Fauzi & Hashim, 2015; Hsu et al., 2017), is any skin care products which can preserve or enhance the natural environment by conserving energy or resources and decreasing or eliminating the usage of harmful agents, pollution, and waste. Studies showed there is an increasing in the consumption of green skincare products and toiletries by 45%, from a peak of RM 1.6 billion (in 1998) to RM 2.2 billion (in 2010), with sales estimated to exceed $1.1 billion in 2010 among young people (Boon et al., 2020). Keywords: Green Skin Care, Generation Z, Theory Of Planned Behaviour

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