scholarly journals Memoirs: On a New Type of Nephridia found in Indian Earthworms of the Genus Pheretima

1919 ◽  
Vol s2-64 (253) ◽  
pp. 67-117
Author(s):  
KARM NARAYAN BAHL
Keyword(s):  
Blood Stream ◽  
The Body ◽  
Coelomic Fluid ◽  
Sphincter Muscle ◽  
Remarkable Feature ◽  
Dorsal Wall ◽  
New Type ◽  
Excretory Canals ◽  
First Time ◽  
Duct Opening

(1) There are three distinct kinds of nephridia in Pheretima posthnma and other species of the genus, namely, the septal, the pharyngeal and the integumentary, named according to the position they occupy in the worm; they differ from each other in size and also in respect of the place of opening of their ducts. (2) Each nephridium is a separate and discrete structure and there is no network of any kind, and therefore the terms "plectonephric" and "diffuse" are inapplicable to these nephridia, although the term "micronephridia" can be retained. (3) The integumentary nephridia are very minute and are hardly visible to the naked eye. Each of them has its own separate duct opening separately to the exterior on the skin. Each, segment has about 200 to 250 of them. The pharyngeal nephridia occur in paired tufts lying at the sides of the oesophagus in the fourth, fifth and sixth segments; these nephridial tufts have three pairs of ducts, one in each segment, which open into the buccal cavity and the pharynx in the second and fourth segments. (4) The septal nephridia are attached to both sides of the septa; they do not open on the skin, but are connected with an elaborate system of ducts which ultimately open into the lumen of the intestine mid-dorsally at segmental intervals. The system of ducts and openings is perfectly segmental in arrangement, and consists of a pair of septal excretory canals on each septum which open into a pair of supra-intestinal excretory ducts lying in the mid-dorsal line of the worm above the dorsal wall of the gut, these ducts communicating with the lumen of the intestine at each intersegmental place by means of a narrow ductule. This last feature is characteristic of this type of nephridial system, and the latter has therefore been termed the "enteronephric" type of nepliridial system. Bach septal nephridium has a remarkable feature in that it lies--the funnel and all--wholly within the bounds of a single segment. The septal canals, the supra-intestinal ducts and their openings into the lumen of the gut have been described here for the first time, and the segmental character of the nephridial system of Pheretima, which was denied by Beddard, has now been established. (5) The enteronephric nephridial system is probably a device for the conservation of water in this tropical genus, the gut-epithelium reabsorbing the water of the excretory fluid while letting the solid excretory matters pass out through the anus along with the fæces. (6) Each nephridium in Pheretima, like that in Lumbricus, is connected with two blood-vessels, one bringing blood to it and the other taking away the blood. The septal and the integumentary nephridia are supplied with blood from the ventral vessel through the parietal vessel and the septal branch, and the blood is returned from these nephridia to the general blood-stream via, the dorso-lateral vessel and the subneural vessel. The pharyngeal nephridia receive their blood-supply from the dorsal vessel, and the blood is returned from them to the lateral cesophageal vessels. (7) The intersegmental septa in Pheretima posthuma and other species have definite, circular or oval apertures, each with a sphincter muscle around it. It is suggested that by closing these apertures by means of sphincters there is a restriction of the cœlomic fluid to certain segments which become consequently turgid and stiff, and are thus able to help the setae in having a firm hold of the ground during the locomotory movements of the animal; this turgidity of the part of the body applying setse on to the ground seems necessary, since a limp part cannot fix its setæ on the substratum on which the worm moves.

Memoirs: Studies on the Structure, Development, and Physiology of the Nephridia of Oligochaeta VI. The Physiology of Excretion and the Significance of the Enteronephric Type of Nephridial System in Indian Earthworms

1945 ◽  
Vol s2-85 (340) ◽  
pp. 343-389
Author(s):  
KARM NARAYAN BAHL
Keyword(s):  
Large Scale ◽  
Body Wall ◽  
Chloride Content ◽  
The Body ◽  
Regulatory Function ◽  
Coelomic Fluid ◽  
Brownish Yellow ◽  
Terrestrial Animal ◽  
First Time ◽  
Blood Pigment

1. In an earthworm, as in most aquatic invertebrates, urea and ammonia form the main bulk of nitrogenous excretion and there is no trace of uric acid. These excretory products are first formed in the body-wall and gut-wall, pass therefrom into the coelomic fluid and blood, and are thence eliminated to the exterior by the nephridia. In Pheretima urea and ammonia pass out from the nephridia to the exterior either directly through the skin or through the two ends of the gut. 2. Ammonia and urea have been estimated for the first time in the blood, coelomic fluid, and urine of the earthworm. It has been shown that blood is not a mere carrier of oxygen, as Rogers believed, but that it also takes part in carrying urea and ammonia from the body-wall and gut-wall to the nephridia. The blood of the earthworm does not coagulate, indicating absence of fibrinogen. 3. The role of the nephridia in excretion and osmotic regulation has been determined. A comparison of the osmotic pressures of blood, coelomic fluid, and urine shows that the coelomic fluid is hypotonic to the blood, and that urine is markedly hypotonic both to the blood and coelomic fluid. The protein and chloride contents of the blood, coelomic fluid, and urine have been determined with a view to elucidate the differences in their osmotic pressures. It has been found that the urine contains the merest trace of protein, but that the amount of proteins in the blood is about eight times that contained in the plasma of the coelomic fluid. On the contrary, the chloride content of the coelomic fluid-plasma is about 60 per cent, higher than that of the blood-plasma. 4. The part of urine which is excreted from the blood is probably a protein-free filtrate, but the nephridia reabsorb all the proteins passing into them with the coelomic fluid-plasma. Similarly, there is a reabsorption of chlorides on a large scale from the initial nephridial filtrate during its passage through the nephridia. 5. A convenient method has been devised for collecting urine of the earthworm, which has made it possible to collect as much as 25 c.c. of urine in two and a half hours. The rate of excretion of the urine has been determined and it has been found that in an earthworm living in water the outflow of urine in twenty-four hours must be more than 45 per cent, of its body-weight. 6. It seems that an earthworm, when submerged in water, can live like a fresh water animal, and its gut acts as an osmoregulatory organ in addition to the nephridia, but in the soil it lives like a terrestrial animal and the osmo-regulatory function is adequately discharged by the nephridia alone which reabsorb chlorides and proteins, and are also active in the conservation of water. In Pheretima and other earthworms with an enteronephric type of nephridial system, the gut takes a prominent part in reabsorbing the water of the nephridial fluid and conserving water to its maximum extent. 7. The phagocytic section (ciliated middle tube) believed by Schneider to be absent in the nephridia of Pheretima has been shown to be distinctly present; it is also present in the nephridia of Lampito , Eutyphoeus, and Tonoscolex. The brownish yellow granules characteristic of this phagocytic section form a heavy deposit in the septal nephridia of Pheretima posthuma, heavier than that described in Lumbricus. The deposit increases with the age of the earthworm and forms a ‘storage excretory product’. 8. Spectroscopic examination has revealed that these brownish yellow granules, so far believed to be of guanine, are really blood-pigment granules, since a pyridine solution of them shows the two characteristic bands of haemochromogen. With regard to the blood-pigment, the nephridia function as ‘storage kidneys’. 9. The mechanism of nephridial excretion of the earthworm can be analysed into processes of filtration, reabsorption, and chemical transformation. 10. It is probable that the dorsal and ventral phagocytic organs of earthworms are additional excretory organs.

A new species of Phreodrilidae (Oligochaeta), Astacopsidrilus naceri sp.nov., from Morocco (North Africa), with notes on the biogeography of the family

1995 ◽  
Vol 73 (12) ◽  
pp. 2375-2381 ◽  
Author(s):  
Narcisse Giani ◽  
Patrick Martin ◽  
Jacques Juget
Keyword(s):  
New Species ◽  
North Africa ◽  
Arabian Peninsula ◽  
The Body ◽  
Dorsal Wall ◽  
The Family ◽  
First Time ◽  
A New Species

Previously only known in Australia and mainly ectoparasitic, the genus Astacopsidrilus has been found in groundwaters of North Africa (Morocco) for the first time. The characteristics of Astacopsidrilus naceri sp.nov. include two setae in ventral bundles, one simple-pointed and one bifid with the upper tooth reduced, deep spermathecal vestibules running to the dorsal wall of the body, with muscular attachment in which the female funnel is probably involved, and sperm organised into thin, elongated, and spirally coiled bundles. The location of the new species in North Africa extends the distribution of the family above the Tropic of Cancer. Compilation of records known thus far supports a pan-Gondwanian origin of the family. The occurrence of the family in refuges above the Tropic of Capricorn led us to assume that the species is a relict in this geographical zone and to predict the existence of the family in groundwaters of Arabian Peninsula.

A Relationship Between the Factor Indivisibility and the Output Elasticity of the Indivisible Factor

2021 ◽  
pp. 232102222098516
Author(s):  
Dipankar Das
Keyword(s):  
Production Function ◽  
Limit Point ◽  
Mathematical Proof ◽  
Wage Equation ◽  
Marginal Value ◽  
Output Elasticity ◽  
New Type ◽  
First Time ◽  
Jel Classifications

The paper puts forth a notion and derives a special type of production function where labour is an indivisible factor and is in the integer space. Thus, Newtonian calculus is not an appropriate method of deriving the marginal value because limit point does not exist. This shows that indivisibility determines the output elasticity. In the first part, the paper propounds a notion regarding how indivisibility determines curvature of the production function. In the second part, the paper incorporates the findings within a production function and derives a new type accordingly. Moreover, it formally derives the standard wage equation considering all the entitlements of labour, namely (a) normal wages, (b) interest and (c) rent of ability. So far, no such mathematical proof is there to support this wage composition. This paper, for the first time, derives this wage equation considering indivisibility of labour. JEL Classifications: J23, J24, J31, D24, C61, E24, L8

scholarly journals Electro-Quasistatic Animal Body Communication for Untethered Rodent Biopotential Recording

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shreeya Sriram ◽  
Shitij Avlani ◽  
Matthew P. Ward ◽  
Shreyas Sen
Keyword(s):  
Lower Energy ◽  
Sensor Node ◽  
State Of The Art ◽  
The Body ◽  
Animal Body ◽  
Current State ◽  
Communication Modalities ◽  
First Time ◽  
Biopotential Recording

AbstractContinuous multi-channel monitoring of biopotential signals is vital in understanding the body as a whole, facilitating accurate models and predictions in neural research. The current state of the art in wireless technologies for untethered biopotential recordings rely on radiative electromagnetic (EM) fields. In such transmissions, only a small fraction of this energy is received since the EM fields are widely radiated resulting in lossy inefficient systems. Using the body as a communication medium (similar to a ’wire’) allows for the containment of the energy within the body, yielding order(s) of magnitude lower energy than radiative EM communication. In this work, we introduce Animal Body Communication (ABC), which utilizes the concept of using the body as a medium into the domain of untethered animal biopotential recording. This work, for the first time, develops the theory and models for animal body communication circuitry and channel loss. Using this theoretical model, a sub-inch$$^3$$ 3 [1″ × 1″ × 0.4″], custom-designed sensor node is built using off the shelf components which is capable of sensing and transmitting biopotential signals, through the body of the rat at significantly lower powers compared to traditional wireless transmissions. In-vivo experimental analysis proves that ABC successfully transmits acquired electrocardiogram (EKG) signals through the body with correlation $$>99\%$$ > 99 % when compared to traditional wireless communication modalities, with a 50$$\times$$ × reduction in power consumption.

scholarly journals Experiential ownership and body ownership are different phenomena

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Caleb Liang ◽  
Wen-Hsiang Lin ◽  
Tai-Yuan Chang ◽  
Chi-Hong Chen ◽  
Chen-Wei Wu ◽  
...  
Keyword(s):  
Conscious Experience ◽  
Distinct Type ◽  
Body Part ◽  
The Body ◽  
Body Ownership ◽  
Rubber Hand ◽  
Person Perspective ◽  
The One ◽  
First Time ◽  
Full Body

AbstractBody ownership concerns what it is like to feel a body part or a full body as mine, and has become a prominent area of study. We propose that there is a closely related type of bodily self-consciousness largely neglected by researchers—experiential ownership. It refers to the sense that I am the one who is having a conscious experience. Are body ownership and experiential ownership actually the same phenomenon or are they genuinely different? In our experiments, the participant watched a rubber hand or someone else’s body from the first-person perspective and was touched either synchronously or asynchronously. The main findings: (1) The sense of body ownership was hindered in the asynchronous conditions of both the body-part and the full-body experiments. However, a strong sense of experiential ownership was observed in those conditions. (2) We found the opposite when the participants’ responses were measured after tactile stimulations had ceased for 5 s. In the synchronous conditions of another set of body-part and full-body experiments, only experiential ownership was blocked but not body ownership. These results demonstrate for the first time the double dissociation between body ownership and experiential ownership. Experiential ownership is indeed a distinct type of bodily self-consciousness.

scholarly journals Normalizing Vision: The Representation and Use of Spectacles and Eyeglasses in Victorian Britain

2021 ◽  
Author(s):  
Gemma Almond
Keyword(s):  
Assistive Technology ◽  
Cultural Context ◽  
Assistive Technologies ◽  
The Body ◽  
Visual Aids ◽  
Medical Texts ◽  
Victorian Britain ◽  
Victorian Period ◽  
First Time ◽  
Material Evidence

Abstract This study explores the representation and use of Victorian visual aids, specifically focusing on how the design of spectacle and eyeglass frames shaped ideas of the ‘normal’ and ‘abnormal’ body. It contributes to our understanding of assistive technologies in the Victorian period by showcasing the usefulness of material evidence for exploring how an object was produced and perceived. By placing visual aids in their medical and cultural context for the first time, it will show how the study of spectacle and eyeglass frames develops our understanding of Victorian society more broadly. Contemporaries drew upon industrialization, increasing education, and the proliferation of print to explain a rise in refractive vision ‘errors’. Through exploring the design of three spectacle frames from the London Science Museum’s collections, this study will show how the representations and manufacture of visual aids transformed in response to these wider changes. The material evidence, as well as contemporary newspapers, periodicals, and medical texts, reveal that visual aids evolved from an unusual to a more mainstream device. It argues that visual aids are a unique assistive technology, one that is able to inform our understanding of how Victorians measured the body and constructed ideas of ‘normalcy’ and ‘abnormalcy’.

scholarly journals Bark traits, decomposition and flammability of Australian forest trees

2017 ◽  
Vol 65 (4) ◽  
pp. 327 ◽  
Author(s):  
Saskia Grootemaat ◽  
Ian J. Wright ◽  
Peter M. van Bodegom ◽  
Johannes H. C. Cornelissen ◽  
Veronica Shaw
Keyword(s):  
Forest Tree ◽  
Remarkable Feature ◽  
Interspecific Differences ◽  
Eucalypt Plantations ◽  
Physical Traits ◽  
Key Driver ◽  
Multiple Species ◽  
Species Specific ◽  
First Time ◽  
Different Tissues

Bark shedding is a remarkable feature of Australian trees, yet relatively little is known about interspecific differences in bark decomposability and flammability, or what chemical or physical traits drive variation in these properties. We measured the decomposition rate and flammability (ignitibility, sustainability and combustibility) of bark from 10 common forest tree species, and quantified correlations with potentially important traits. We compared our findings to those for leaf litter, asking whether the same traits drive flammability and decomposition in different tissues, and whether process rates are correlated across tissue types. Considerable variation in bark decomposability and flammability was found both within and across species. Bark decomposed more slowly than leaves, but in both tissues lignin concentration was a key driver. Bark took longer to ignite than leaves, and had longer mass-specific flame durations. Variation in flammability parameters was driven by different traits in the different tissues. Decomposability and flammability were each unrelated, when comparing between the different tissue types. For example, species with fast-decomposing leaves did not necessarily have fast-decomposing bark. For the first time, we show how patterns of variation in decomposability and flammability of bark diverge across multiple species. By taking species-specific bark traits into consideration there is potential to make better estimates of wildfire risks and carbon loss dynamics. This can lead to better informed management decisions for Australian forests, and eucalypt plantations, worldwide.

scholarly journals Structural, Superconducting and Magnetic Properties of La3-XRxNi2B2N3-δ with R = Ce, Pr, Nd

2011 ◽  
Vol 170 ◽  
pp. 165-169 ◽  
Author(s):  
Tahir Ali ◽  
Ernst Bauer ◽  
Gerfried Hilscher ◽  
Herwig Michor
Keyword(s):  
Magnetic Properties ◽  
Structure Type ◽  
The Body ◽  
Spin Reorientation ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
Range Magnetic Order ◽  
Long Range Magnetic Order ◽  
First Time ◽  
Magnetic Pair

We report on structural and superconducting properties of La3-xRxNi2B2N3- where La is substituted by the magnetic rare-earth elements Ce, Pr, Nd. The compounds Pr3Ni2B2N3- and Nd3Ni2B2N3- are characterized for the first time. Powder X-ray diffraction confirmed all samples R3Ni2B2N3- with R = La, Ce, Pr, Nd and their solid solutions to crystallize in the body centered tetragonal La3Ni2B2N3 structure type. Superconducting and magnetic properties of La3-xRxNi2B2N3- were studied by resistivity, specific heat and susceptibility measurements. While La3Ni2B2N3- has a superconducting transition temperature Tc ~ 14 K, substitution of La by Ce, Pr, and Nd leads to magnetic pair breaking and, thus, to a gradual suppression of superconductivity. Pr3Ni2B2N3- exibits no long range magnetic order down to 2 K, Nd3Ni2B2N3- shows ferrimagnetic ordering below TC =17 K and a spin reorientation transition to a nearly antiferromagnetic state at 10 K.

Ionic regulation and buoyancy in some planktonic organisms

1993 ◽  
Vol 73 (1) ◽  
pp. 15-23 ◽  
Author(s):  
C. Newton ◽  
W. T. W. Potts
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
The Body ◽  
Coelomic Fluid ◽  
Ionic Regulation ◽  
High Concentration ◽  
Emission Analysis ◽  
X Ray ◽  
Scanning Electron ◽  
Gastrovascular System

Magnesium/chlorine and sulphur/chlorine ratios have been measured in the body fluids of some planktonic organisms by x-ray emission analysis of frozen hydrated specimens in a scanning electron microscope. Homarus vulgaris (Anthropoda: Decapoda) larvae excluded Mg2+ and SO42-ions from the haemolymph, but to a lesser extent than does the adult lobster. Bipinnaria larvae of Asterias (Echinodermata) excluded Mg2+ and SO42-ions from the coelomic fluid. Obelia medusae excluded Mg2+ and SO42-ions from the mesogloea but concentrate them in the gastrovascular system. The high concentration of sulphate in the gastrovascular fluid of medusae has been confirmed by rhodizonate titration in Cyanea and Rhizostoma jellyfish. Some implications of magnesium and sulphate regulation are discussed.

scholarly journals A Novel Six-Rhodopsin System in a Single Archaeon

2010 ◽  
Vol 192 (22) ◽  
pp. 5866-5873 ◽  
Author(s):  
Hsu-Yuan Fu ◽  
Yu-Cheng Lin ◽  
Yung-Ning Chang ◽  
Hsiaochu Tseng ◽  
Ching-Che Huang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Global Environment ◽  
Diverse Group ◽  
Ion Transporters ◽  
Haloarcula Marismortui ◽  
Resource Limited ◽  
New Type ◽  
Ion Transportation ◽  
Proton Transporters ◽  
First Time

ABSTRACT Microbial rhodopsins, a diverse group of photoactive proteins found in Archaea, Bacteria, and Eukarya, function in photosensing and photoenergy harvesting and may have been present in the resource-limited early global environment. Four different physiological functions have been identified and characterized for nearly 5,000 retinal-binding photoreceptors, these being ion transporters that transport proton or chloride and sensory rhodopsins that mediate light-attractant and/or -repellent responses. The greatest number of rhodopsins previously observed in a single archaeon had been four. Here, we report a newly discovered six-rhodopsin system in a single archaeon, Haloarcula marismortui, which shows a more diverse absorbance spectral distribution than any previously known rhodopsin system, and, for the first time, two light-driven proton transporters that respond to the same wavelength. All six rhodopsins, the greatest number ever identified in a single archaeon, were first shown to be expressed in H. marismortui, and these were then overexpressed in Escherichia coli. The proteins were purified for absorption spectra and photocycle determination, followed by measurement of ion transportation and phototaxis. The results clearly indicate the existence of a proton transporter system with two isochromatic rhodopsins and a new type of sensory rhodopsin-like transducer in H. marismortui.

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