Galvanotropic Reactions of Polycelis nigra in Relation to Inherent Electrical Polarity

1927 ◽  
Vol 5 (1) ◽  
pp. 66-88
Author(s):  
J. ARMITAGE ROBERTSON
Keyword(s):  
Electrical Circuit ◽  
The Body ◽  
Constant Current ◽  
Forward Movement ◽  
Electrical Currents ◽  
Turning Mechanism ◽  
Electrical Polarity ◽  
Metabolic Activities ◽  
Physiological Gradients ◽  
A Current

The galvanotropic reactions of Polycelis nigra were investigated in constant and "intermittent" (that is, a current showing slight commutator ripple) electrical currents, varying in strength from one to about ten milliamperes. Galvanotropic reactions were most readily forthcoming at about 2 m.a. constant current, higher current strengths producing signs of discomfort or rigor, and intermittent current being slightly more effective in producing such disturbances than constant current. As a rule, Polycelis places itself longitudinally, with head facing the kathode, and moves thither by means of looping, its normal gliding motion being in abeyance. If facing the kathode on application of the current, it simply loops forward, but if moving parallel to the electrodes it turns its anterior end first, and then movesmore or less directly towards the kathode. If previously facing the anode, a turn in the direction of the kathode is usually accomplished only after more or less headwaving and apparent difficulty or hesitation. Decapitate animals, if facing the anode in the current, at some time or other almost invariably loop backwards to the kathode, tail foremost, for a varying number of times, before turning their anterior end to the kathode and orientating normally. This was never observed in normal animals. Decaudate animals behave like unmutilated individuals. Decapitate-and-decaudate Polycelis (middle-pieces) reactin the same manner as do decapitate specimens, i.e. show backward looping. Longitudinal halves of Polycelis are usually curved towards the injured side, and show little or no movement, either in or out of the current; it is supposed that this curvature is mechanical and the result of the injury. Higher amperages (above 2 m.a.) produce, progressively, cessation of forward movement with twisting and apparent discomfort, and, finally, flattening of the kathodic end of the body. This last reaction is often accompanied by various postures, presumably the result of arrested movement. An explanation of these reactions, in normal and unmutilated animals, is attempted, based on the supposed interaction of the experimental current with the external portion of an inherent electrical circuit. If this inherent circuit be obstructed it is suggested that the metabolic activities, with which it is apparently correlated, are to some extent upset. Further, that to avoid this derangement, and concomitant malaise, the animals orientate themselves so that the experimental current does not flow counter to the external portion of their inherent circuit; that the turning mechanism of the flanks which affects this orientation can be explained upon similar grounds; finally that backward looping can be explained as a transference of control or dominance to the tail end, due to the combined inhibitory action of mutilation and of a contrary experimental current upon the normal physiological gradients at the anterior end. A variety of points related to the theory, and some cases of galvanotropism bearing on the work, together with their theoretical explanations, are discussed.

Transplantations de gonades indifférenciées chez l'hermaphrodite simultané Eisenia foetida (Oligochète, Lumbricidae)

Development ◽  
1973 ◽  
Vol 30 (1) ◽  
pp. 143-161
Author(s):  
Par J. C. Relexans
Keyword(s):  
Nervous System ◽  
Sexual Differentiation ◽  
The Body ◽  
Simultaneous Hermaphrodite ◽  
Eisenia Foetida ◽  
Turn On ◽  
Opposite Sex ◽  
Adjacent Wall ◽  
Physiological Gradients ◽  
Different Parts

Transplantations of undifferentiated gonads in the simultaneous hermaphrodite Eisenia foetida (Oligochaeta, Lumbricidae) leading to evidence of local factors (inductors?) of sexual differentiation The hypothesis of a ♀ sex capable of autodifferentiation and of a ♂ sex depending on an androgen hormone has been verified in several gonochoric or hermaphrodite invertebrates. In order to test the validity of this hypothesis in the hermaphrodite Eisenia foetida we have investigated the influence of the gonads' environment on their differentiation by transplanting undifferentiated gonads, dorsally and ventrally, on different parts of the body. The gonads, taken with the adjacent wall of the body from new-born worms, are grafted on worms of the same age; some grafts do, others do not, retain their nervous system. The control transplantation in which a graft of a given presumptive sex is transplanted in a region of the same sex can lead to inversions. These inversions have a rare and short-lived character in the gonads coming from presumptive testes. They are more frequent and more or less durable in the gonads coming from presumptive ovaries. These results can only be explained by the existence, within the grafts of the two presumptive sexes, of a dominant relationship between one and the other sexual potentiality which can be momentarily inverted by trophic disturbances caused by the transplantation. The heterosexual transplantations, in which a graft of a given presumptive sex is transplanted in the region of the opposite sex, show that the frequency of the inversions is doubled in relation to the frequency obtained in the control transplantations. The inversions which occur in the presumptive testes can be lasting and even permanent. These results lead to the opinion that to the effects of transplantation is added an inductive action from the host, leading to masculinity in the ♂ region and femininity in the ♀ region. The transplantations outside of the sexual ventral regions lead to inversions of which the character and frequency recall those obtained in the control transplantations. They suggest that these regions are devoid of inductive sexualizing power. The very slight variations of frequency of the inversions observed along the antero-posterior and dorso-ventral axes can be explained by the existence of physiological gradients acting on the balance of the graft's own potentialities. The removal of the nervous system in the grafts shows that this system plays a part, probably trophic, in favour of the masculine potentialities of the graft. In conclusion, our experiments lead to the rejection of the hypothesis of the ♀ sex capable of autodifferentiation in Eisenia, in order to adopt that of a sexual balance between the ♂ and ♀ potentialities determining, according to their dominant relationship, the synthesis of ♂ or ♀ ‘inductors’ respectively in the ♂ and ♀ ventral regions. These inductors act in turn on the bipotential sexual cells.

scholarly journals Connection of Body Temperature with Fear of Rides

2019 ◽  
Vol 4 (2) ◽  
Keyword(s):  
Body Temperature ◽  
The Body ◽  
Normal Value ◽  
Mercury Thermometer ◽  
Metabolic Activities

The present study was done in order to evaluate connection between body temperature and fear of rides. About 120 disciples of Baha Uddin Zakariya University took part in this study. Isothermal, also known as the normal temperature of body is one of the most important factors in maintaining the metabolic activities of the body that are vital for life. It normal value is 37 °C. It can be measured by using mercury thermometer [1]. It is measured on certain body positions like forehead, mouth and rectum. Fear of rides is common among people who have other phobias like claustrophobia, acrophobia etc. Those people whose body temperature is 97 are more afraid of rides as compared to those people who have low body temperature.

The Mechanism of Proboscis Movement in Arenicola

1954 ◽  
Vol s3-95 (30) ◽  
pp. 251-270
Author(s):  
G. P. WELLS
Keyword(s):  
Body Fluid ◽  
Body Wall ◽  
The Body ◽  
Stage I ◽  
Stage Iii ◽  
Forward Movement ◽  
Arenicola Marina ◽  
Buccal Mass ◽  
The Difference ◽  
Longitudinal Muscles

The mechanism of proboscis movement is analysed in detail in Arenicola marina L. and A. ecaudata Johnston, and discussed in relation to the properties of the hydrostatic skeleton. Proboscis activity is based on the following cycle of movements in both species. Stage I. The circular muscles of the body-wall and buccal mass contract; the head narrows and lengthens. Stage IIa. The circular muscles of the mouth and buccal mass relax; the gular membrane (or ‘first diaphragm’ of previous authors) contracts; the mouth opens and the buccal mass emerges. Stage IIb. The longitudinal muscles of the buccal mass and body-wall contract; the head shortens and widens and the pharynx emerges. Stage III. As Stage I. The two species differ anatomically and in their hydrostatic relationships. In ecaudata, the forward movement of body-fluid which extrudes and distends the proboscis is largely due to the contraction of the gular membrane and septal pouches. In marina, the essential mechanism is the relaxation of the oral region which allows the general coelomic pressure to extrude the proboscis. The gular membrane of marina contracts as that of ecaudata does, but its anatomy is different and it appears to be a degenerating structure as far as proboscis extrusion is concerned. Withdrawal of the proboscis may occur while the head is still shortening and widening in Stage IIb, or while it is lengthening and narrowing in Stage III. The proboscis is used both in feeding and in burrowing; in the latter case nothing enters through the mouth; the difference is largely caused by variation in the timing of withdrawal relative to the 3-stage cycle.

Experiments with P32 and I131 on Species of Helix, Arion, and Agriolimax

1952 ◽  
Vol s3-93 (22) ◽  
pp. 133-146
Author(s):  
VERA FRETTER
Keyword(s):  
Salivary Glands ◽  
Digestive Gland ◽  
Radioactive Iodine ◽  
Helix Pomatia ◽  
Relative Activity ◽  
The Body ◽  
Ionic Exchange ◽  
Digestive Cells ◽  
Metabolic Activities ◽  
Calcium Cells

If Helix aspersa, H. pomatia, Arion hortensis, and Agriolimax agrestis be fed on a diet which contains P32, autoradiographs show that the isotope is taken up by the digestive and lime cells of the digestive gland. From the formermost of it passes to the haemocoel, though some is retained for immediate metabolic activities; in the lime cells it is stored in calcium spherules. A very small amount of the tracer enters the body through the wall of the oesophagus, and more through the intestine, this site of diffusion being most pronounced directly after hibernation. The P33 in the haemocoel is dispersed to all tissues: all of them take up a little; in some it becomes concentrated. Concentrations appear in the nerve ring, the mucous and salivary glands, the odontophore and certain cells of the mantle. In the nervous system deposits are heavy around the fibres and slight in the cytoplasm of the cells; they indicate a compound, soluble in alcohol, which may be phospholipine, associated with medullated nerves. The phosphorus in mucous cells, most pronounced in the pedal and salivary glands, may be combined with the calcium which stabilizes mucus and prevents its rapid dispersal. The incorporation of isotope into the developing tooth of the radula indicates the relative activity of the basoblasts and cuspidoblasts: in early development of a tooth the basoblast secretes more actively, but as it becomes effete secretion by the cuspidoblast is accelerated. When the tooth is liberated from the latter there is no further addition to its substance. Phosphorus deposits in the mantle are in the calcium cells which secrete the shell. Here, as in the lime cells, and around certain blood-vessels, excess may be stored as calcium phosphate; reserves in the digestive gland are the largest. Amoebocytes concerned with the regeneration of the shell of Helix pomatia and H. aspersa carry the tracer element, and some of it is deposited in the shell. Also in the slug the tracer is transported by amoebocytes. Radioactive iodine in the lumen of the gut is taken up most readily by digestive cells; some enters the lime cells. Only in sparing quantities does this isotope pass from the gland to the rest of the body, and this entry is presumably associated with ionic exchange. It is not accumulated in any cell, except in the kidney whence it is excreted; it leaves the digestive cells to pass from the body with the faeces.

scholarly journals Doing nothing does something: Embodiment and data in the COVID-19 pandemic

2020 ◽  
Vol 7 (1) ◽  
pp. 205395172093393
Author(s):  
Mickey Vallee
Keyword(s):  
Public Health ◽  
Media Studies ◽  
Common Good ◽  
Current Data ◽  
The Body ◽  
Health Crisis ◽  
Critical Data ◽  
The Social ◽  
The Common ◽  
A Current

The COVID-19 pandemic redefines how we think about the body, physiologically and socially. But what does it mean to have and to be a body in the COVID-19 pandemic? The COVID-19 pandemic offers data scholars the unique opportunity, and perhaps obligation, to revisit and reinvent the fundamental concepts of our mediated experiences. The article critiques the data double, a longstanding concept in critical data and media studies, as incompatible with the current public health and social distancing imperative. The data double, instead, is now the presupposition of a new data entity, which will emerge out of a current data shimmer: a long-sustaining transition that blurs the older boundaries of bodies and the social, and establishes new ethical boundaries around the (in)activity and (im)mobility of doing nothing to do something. The data double faces a unique dynamic in the COVID-19 pandemic between boredom and exhaustion. Following the currently simple rule to stay home presents data scholars the opportunity to revisit the meaning of data as something given, a shimmering embodied relationship with data that contributes to the common good in a global health crisis.

III.—The Response of Human Motor Nerve to Rectangular Electric Pulses Applied Through Electrodes Placed on the Skin

1967 ◽  
Vol 70 (1) ◽  
pp. 49-61
Author(s):  
W. G. S. Stephens
Keyword(s):  
Motor Nerve ◽  
Rectangular Pulse ◽  
Electrical Circuit ◽  
The Body ◽  
Output Impedance ◽  
Electric Pulses ◽  
Impedance Characteristics ◽  
Human Motor ◽  
Pulse Stimulation ◽  
Good Agreement

SynopsisThe passive electrical impedance characteristics exhibited by the body during rectangular pulse stimulation are analysed, and typical observed properties are specified in terms of the parameters of an equivalent electrical circuit. Equations are derived which describe the current waveform generated in such a circuit by a rectangular pulse stimulator of known finite output impedance. The response of nerve to currents of this form is analysed, and equations are derived which permit the comparison of threshold and intensity-duration data obtained with stimulators of different output impedances. Results predicted by the theory are shown to be in good agreement with experimental results.

THE DESIGN OF A LI-ION BATTERY CHARGER BASED ON MULTIMODE LDO TECHNOLOGY

2009 ◽  
Vol 18 (05) ◽  
pp. 947-963 ◽  
Author(s):  
CHIA-CHUN TSAI ◽  
CHIN-YEN LIN ◽  
YUH-SHYAN HWANG ◽  
TRONG-YEN LEE
Keyword(s):  
Power Efficiency ◽  
Input Voltage ◽  
Constant Current ◽  
Voltage Regulator ◽  
Cmos Process ◽  
Li Ion Battery ◽  
Battery Charger ◽  
Charging Current ◽  
Li Ion ◽  
A Current

In this paper, we design a CMOS Li-Ion battery charger using the multimode low dropout (LDO) voltage regulator associated with a current sense to supply trickle current, constant current, and constant voltage for charging the battery in order. The protections from over charging and discharging are also considered by monitoring the charging current, reverse voltage, and battery temperature. The whole charger has been verified by HSPICE with TSMC 0.35 μm 2P4M CMOS process. The charger provides the trickle current of 150 mA, maximum charging current of 312 mA, and charging voltage of 4.2 V at the input voltage of 4.5 V. The power efficiency of 72.3% is acceptable under the power consumption of 1.28 W. The chip occupies an area of 1.78 mm × 1.77 mm including 2955 transistors.

Defining a Parameter of Effectiveness for the Suppression of Vortex-Induced Vibration

2011 ◽  
Author(s):  
Cesar M. Freire ◽  
Ivan Korkischko ◽  
Julio R. Meneghini
Keyword(s):  
Shear Layers ◽  
The Body ◽  
Bluff Bodies ◽  
Vortex Induced Vibration ◽  
Vibration Effect ◽  
Splitter Plates ◽  
Offshore Engineering ◽  
Flow Mechanisms ◽  
Offshore Industry ◽  
A Current

The vortex-induced vibration (VIV) phenomenon is a very important issue in ocean and offshore engineering. When bluff bodies are immersed in a current, the boundary layers separate and form shear layers that can interact causing a periodic vortex shedding. In such condition, the forces acting on the body can make it vibrate. In the offshore industry, among other engineering applications, the vibration of structures can cause fatigue problems, reducing the life span of the element. To reduce the vortex-induced vibration effect suppressors can be employed in order to avoid the body to move, or at least, reduce the amplitude of vibration. There is a great number of suppressor types, like strakes, splitter plates, shrouds, etc; and each one has its own flow mechanisms to avoid VIV. Until now there is no simple way to compare the results and effectiveness of each suppressor. The purpose of this work is to define a parameter called suppressor effectiveness, based on the amplitude of vibration and the reduced velocity range, and use the suppressor effectiveness to compare different suppressors. The data used in the comparisons was obtained from experiments by the authors and collected from the literature.

Quantitative analysis of prey-capture kinematics in Anolis equestris (Reptilia: Iguanidae)

1990 ◽  
Vol 68 (10) ◽  
pp. 2192-2198 ◽  
Author(s):  
Vincent L. Bels
Keyword(s):  
High Speed ◽  
Prey Capture ◽  
Anterior Part ◽  
The Body ◽  
Original Position ◽  
Forward Movement ◽  
Live Prey ◽  
Capture Process ◽  
Locomotor System ◽  
Cyclic Movement

High-speed cinematography was employed to study the mechanics of prey capture in Anolis equestris. Capture of live prey (adult locusts) consists of a cyclic movement of the upper and lower jaws combined with tongue protraction. Kinematic profiles are presented for the jaws, tongue, and forelimbs. The tongue is projected during the "slow open" stage and most of the "fast open" stage. The tongue protrudes beyond the mandibular symphysis during the slow open stage, and rotates simultaneously around a transverse anteromedian axis. The prey is thus contacted by the dorsal sticky surface of the tongue, and then pulled backward into the oral cavity by a combination of a forward movement of the jaws and retraction of the tongue. Gape angle, defined as the angle between the upper and lower jaws, continues to increase during the initial stages of tongue retraction. During the capture process, the anterior part of the body lunges forward, followed by a return to its original position; this displacement is mediated by the forelimbs, which usually remain well anchored to the floor. The cyclic food-capture movements of the jaws and tongue–hyoid system in A. equestris (Iguanidae) and Chameleo dilepis (Chamaeleontidae) are compared. I argue that one of the primary selection forces in the evolution of the different mechanisms of prey prehension in these two lizard groups was enhancement of the locomotor system and, consequently, foraging ability.

scholarly journals Fabrication and Characterization of Porous Silicon Layer Prepared by Photo-Electrochemical Etching in CH3OH:HF Solution

2013 ◽  
Vol 8 ◽  
pp. 29-36 ◽  
Author(s):  
Hasan A. Hadi ◽  
Raid A. Ismail ◽  
Nadir F. Habubi
Keyword(s):  
Porous Silicon ◽  
Electrochemical Etching ◽  
Gravimetric Method ◽  
Silicon Layer ◽  
Porous Silicon Layer ◽  
Constant Current ◽  
Theoretical Relation ◽  
Fabrication And Characterization ◽  
A Current

Porous silicon (PS) has been fabricated by Photo-electrochemical etching. Porous silicon was anodized on n-type Si in light using a current density of 20 mA/cm2 for 10 min. The porous structure formation was confirmed using XRD and AFM studies. The root mean square (RMS) roughness of the Porous silicon layer is found to be around 47.5 nm and the ten point height was 317 nm. The average of pores diameter was 419.98nm, and the grain growth is columnar with a (211) preferred orientation. The grain size of the PS was estimated from the Scherer’s formula and found to be 73 nm. All the properties of the porous silicon layer, such as porosity and the thickness depend on the anodization parameters. The porosity (P) was approximately 77%. The thickness of the layer formed during an anodization in constant current was 3.54 nm in gravimetric method, while its value was 1.77 nm by using the theoretical relation.

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