scispace - formally typeset
Search or ask a question

Showing papers by "University of Leicester published in 1968"


Journal ArticleDOI
TL;DR: The current conceptualization of homosexuality as a condition is a false one, resulting from ethnocentric bias as mentioned in this paper, and it should be seen rather as a social role rather than a social condition.
Abstract: The current conceptualization of homosexuality as a condition is a false one, resulting from ethnocentric bias. Homosexuality should be seen rather as a social role. Anthropological evidence shows that the role does not exist in all societies, and where it does it is not always the same as in modern western societies. Historical evidence shows that the role did not emerge in England until towards the end of the seventeenth century. Evidence from the “Kinsey Reports shows that, in spite of the existence of the role in our society, much homosexual behavior occurs outside the recognized role and the polarization between the heterosexual man and the homosexual man is far from complete.

405 citations


Journal ArticleDOI
TL;DR: In this paper, the drift velocity of excess electrons in solid and liquid Ar, Kr, and Xe was investigated over a range of applied fields from 10 V to 100 kV, and the results indicated that the deviations from the Shockley theory at higher electron temperatures are associated with an increase in the value of the structure factor.
Abstract: This paper reports an investigation of the drift velocity of excess electrons in solid and liquid Ar, Kr, and Xe. After purification of the commercially available gas, thin crystal specimens (100-600 \ensuremath{\mu}m) were grown from the liquid between parallel electrodes in a chamber attached to a miniature cryostat. Pulses of 40-keV electrons were used to generate the charge carriers in both liquids and solids. This technique overcomes the limitations inherent in previously applied methods and has made it possible to investigate the drift velocity over a range of applied fields from 10 V ${\mathrm{cm}}^{\ensuremath{-}1}$ to 100 kV ${\mathrm{cm}}^{\ensuremath{-}1}$. Near the triple point, the low-field mobility ${\ensuremath{\mu}}_{0}$ in solid Ar, Kr, and Xe was found to be 1000, 3700, and about 4500 ${\mathrm{cm}}^{2}$${\mathrm{sec}}^{\ensuremath{-}1}$${\mathrm{V}}^{\ensuremath{-}1}$, respectively. In the liquids the corresponding mobilities were 475, 1800, and 2200 ${\mathrm{cm}}^{2}$${\mathrm{sec}}^{\ensuremath{-}1}$${\mathrm{V}}^{\ensuremath{-}1}$. The temerature dependence of ${\ensuremath{\mu}}_{0}$ has been measured on Ar crystals, and the results indicate that ${\ensuremath{\mu}}_{0}$ is determined by acoustic scattering. The electron lifetime appears to be controlled predominantly by oxygen impurities. Pronounced hot-electron effects are observed in drift-velocity---versus---field curves for both liquids and solids, and their fit to the Shockley hot-electron theory has been investigated. In the high-field region all the curves show an almost complete saturation with field. The theory of Cohen and Lekner applied to liquid Ar fits the results over most of the field range, suggesting that the deviations from the Shockley theory at higher electron temperatures are associated with an increase in the value of the structure factor. In solid Ar or Kr, positive holes do not appear to be mobile, but in Xe crystals a hole mobility of about 2\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}2}$ ${\mathrm{cm}}^{2}$${\mathrm{sec}}^{\ensuremath{-}1}$${\mathrm{V}}^{\ensuremath{-}1}$ was found. The implications of these results are briefly discussed.

289 citations


Journal ArticleDOI
TL;DR: A simplified procedure permits the separation of spinach chloroplasts which retain the ability to catalyze the photosynthetic assimilation of carbon dioxide and its associated oxygen evolution.
Abstract: A simplified procedure (involving disruption in sorbitol-pyrophosphate mixtures) permits the separation of spinach chloroplasts which retain the ability to catalyze the photosynthetic assimilation of carbon dioxide and its associated oxygen evolution

151 citations


Journal ArticleDOI
20 Jul 1968-Nature
TL;DR: This work has shown that the modifying effect on enzyme activity probably results from an induced conformational change in the enzyme structure.
Abstract: THE regulation of enzyme activity by cellular metabolites in micro-organisms is usually exerted by feedback control, an initial enzyme of a pathway being controlled by an end-product of that pathway. Such control of enzyme activity has, in many cases, been shown to be “allosteric”—that is, the end-product effector binds to the enzyme at a site distinct from the catalytic (active) site. The modifying effect on enzyme activity probably results from an induced conformational change in the enzyme structure.

108 citations


Journal ArticleDOI
10 Aug 1968-Nature
TL;DR: SODIUM and potassium concentrations in human red cells are controlled by the sodium pump, and if passive leaks exceed rates of active transport cells undergo colloid osmotic haemolysis, and passive permeability is involved in regulating ionic composition.
Abstract: SODIUM and potassium concentrations in human red cells are controlled by the sodium pump, and if passive leaks exceed rates of active transport cells undergo colloid osmotic haemolysis. Because the sodium pump has a maximum rate1,2, passive permeability is also involved in regulating ionic composition. Is passive permeability, like active transport, related to the metabolic state of the cell ?

91 citations


Journal ArticleDOI
TL;DR: Observations suggest that there is competition between Na(+) and K(+) at the K(+)-sensitive site of the membrane.
Abstract: 1. A study has been made of the interaction between Na+ and K+ on the adenosine triphosphatase activity of erythrocyte `ghosts', and on the K+ influx and Na+ efflux of intact erythrocytes. The adenosine triphosphatase activity and the ion movements were greater at a low external K+ concentration in the absence of Na+ than they were in the presence of 150mm-Na+. The inhibition by external Na+ of K+ influx had an inhibitory constant of 5–10mm. 2. Activation by K+ of kidney microsomal adenosine triphosphatase was retarded by Na+, and activation by Na+ was retarded by K+. Fragmented erythrocyte membranes behaved similarly. 3. These observations suggest that there is competition between Na+ and K+ at the K+-sensitive site of the membrane.

66 citations


Journal ArticleDOI
TL;DR: In this article, the present state of the theory of proportional counter resolution is reviewed and it is shown that anode wire uniformity is a critical factor and that window effects are of litte importance.

63 citations



Journal ArticleDOI
TL;DR: Pituitary glands of Xiphophorus lost more acidophilia and weight from the prolactin cells when cultured on dilute media than on concentrated media.

57 citations


Journal ArticleDOI
TL;DR: A positive and significant correlation was obtained between the score derived from a biographical motion sickness questionnaire (MSQ) and the rate at which spiral after-effect persistence increased as a logarithmic function of the induction period (SAE slope score).
Abstract: This paper reports two experiments designed to elucidate those sensory characteristics which influence motion sickness susceptibility. In the first, a positive and significant correlation was obtained between the score derived from a biographical motion sickness questionnaire (MSQ) and the rate at which spiral after-effect persistence increased as a logarithmic function of the induction period (SAE slope score). A positive but insignificant relation was also found between the MSQ score and the slope of the sensation cupulogram. The second experiment revealed a significant concordance between the MSQ score, the SAE slope score and the slope of the psychophysical function describing individual loudness estimates of a 1000 c/s tone. The notion of ‘receptivity’ was advanced to account for these findings.

56 citations



Journal ArticleDOI
TL;DR: The contractile effects of calcium or barium were antagonized by the addition to the perfusing fluid of several anti‐inflammatory substances, certain local anaesthetics and certain spasmolytic drugs.
Abstract: 1. The rat isolated anterior mesenteric artery was perfused at a constant rate with a calcium-free depolarizing solution. Injection close to the cannula of 0.05-0.1 ml. of solutions of CaCl2 (117 mM) or BaCl2 (100 mM) caused a rise in perfusion pressure. 2. The responses to injected CaCl2 solution could be obtained repeatedly but those to successive injections of BaCl2 solution slowly declined. When the responsiveness to barium had almost disappeared, it could be restored by the addition to the perfusing fluid of a small amount of calcium (0.05 mM). 3. The contractile effects of calcium or barium were antagonized by the addition to the perfusing fluid of several anti-inflammatory substances, certain local anaesthetics and certain spasmolytic drugs. 4. Perfusion of the mesenteric artery with a depolarizing solution containing 0.2 mM-CaCl2 caused a persistent rise of the perfusion pressure. This was rapidly and completely reversed by the addition of indomethacin (4 mg/100 ml.) or cinchocaine hydrochloride (2 mg/100 ml.) to the perfusing fluid. 5. The uptake of 45Ca by rat aorta depleted of calcium was reduced by amethocaine hydrochloride (10 mg/100 ml.) or cinchocaine hydrochloride (2 mg/100 ml.) but not by indomethacin (10 mg/100 ml.) or desipramine hydrochloride (1 mg/100 ml.).

Journal ArticleDOI
TL;DR: In this article, it is suggested that traffic light green times should be adjusted to balance the QUEUES on its VARIOUS ARMS DURING CONDITIONS OF HEAVY CONGESTION.

Journal ArticleDOI
TL;DR: In this paper, the authors have shown that the glacial drifts of central Leicestershire are composed of a basal sand and gravel overlain by a complex succession of tills and interbedded waterlaid sediments, and that the vast majority of the drifts belong to the Saalian glaciation.
Abstract: A programme of mapping and augering has shown the glacial drifts of central Leicestershire to consist of a basal sand and gravel overlain by a complex succession of tills and interbedded waterlaid sediments. The tills display a transition from materials of predominantly north-western derivation to those of north-eastern derivation. Arguments are adduced by which the succession is correlated with that described by Shotton in Warwickshire, and it is concluded that the vast majority of the drifts belong to the Saalian glaciation. A widespread but discontinuous horizon of sand and gravel is believed to denote a temporary melt phase in the middle of the glaciation, while more limited beds of stoneless silt and clay betoken still-water sedimentation which, south of Leicester, is regarded as the local equivalent of the lacustrine Wolston clay of Warwickshire. Although the bedrock surface over most of central Leicestershire has a form consistent with an origin by normal stream erosion, there remain a number of areas where it is difficult to sustain such an interpretation. At Narborough excavations and augering have revealed virtually the full drift succession cut by a series of normal faults traceable over a distance of at least a mile. Near these faults there is evidence of an enclosed depression scored into bedrock and filled with water-laid drift. Although subsequent to the deposition of the drift, the faults have no surface expression at the present time, the structures being truncated by an early post-glacial erosion surface. Later phases in the post-glacial evolution of the Soar and Wreak valleys are associated with a suite of river terraces which, from their included fauna, span the period of the Eemian interglacial and the Weichselian glaciation.


Journal ArticleDOI
TL;DR: In this article, the use of channel multipliers for the photo-electric detection of X-radiation in the wavelength range 2.1 - 67 A has been investigated, and the results of an investigation into the X-ray response and spatial resolution of a channel multiplier array are also presented.
Abstract: The use of channel multipliers for the photo-electric detection of X-radiation in the wavelength range 2.1 - 67 A has been investigated. Measurements of photon detection efficiency are presented for a bare channel multiplier and for multipliers specially coated with photoemissive materials. The variation of photon detection efficiency with angle of incidence is shown to be in fair agreement with that predicted by an analysis of the X-ray photo-electric response of a cylindrical photo-cathode. The surface yields derived from the measurements for Li F and MgF2 are compared with other published data, based on plane photo-cathode measurements, and shown to be in good agreement. A specific application of the channel multiplier in X-Ray Astronomy is described. The results of an investigation into the X-ray response and spatial resolution of a channel multiplier array are also presented. The measured resolution is close to the expected value. The application of arrays of channel multipliers to image dissection in X-ray spectroscopy is discussed.

Journal ArticleDOI
14 Dec 1968-Nature
TL;DR: The experiment reported here describes imprinting in young guinea-pigs, judged in terms of the animals' preference for familiar, compared with strange, objects.
Abstract: CLASSICAL, imprinting of precocial birds has been studied in the laboratory for some 20 years. Suggestions have also been made over a similar period about the imprinting of precocial mammals, but no systematic experiments specifically concerned with imprinting have been reported so far. Although Shipley's study of guinea-pigs1 referred to imprinting, in reality it was concerned with the approaches and following responses of these animals to moving objects. Imprinting involves more than that, namely an attachment to a given figure, and this can be readily assessed in a discrimination test2. The experiment reported here describes imprinting in young guinea-pigs, judged in terms of the animals' preference for familiar, compared with strange, objects.

Journal ArticleDOI
01 Jan 1968-Nature
TL;DR: In this paper, it has been shown that small partial pressures of condensable vapours (for example, 3 torr of water vapour or 0.5 × 10−3 tor r of 1-Br-pentane) can restore the coefficient of friction and the wear rate of graphite to their low values.
Abstract: IT is well known that under vacua of less than 1 torr the coefficient of friction of graphite on itself and other materials increases from its usual value of about 0.15 to a value of 0.5, or even higher, and that the wear rate of the graphite becomes very high. Furthermore, it has been shown1 that small partial pressures of condensable vapours (for example, 3 torr of water vapour or 0.5 × 10−3 torr of 1-Br-pentane) can restore the coefficient of friction and the wear rate to their low values, and it is therefore clear that the normal low friction behaviour of graphite is a result of the presence of condensable vapours.

Journal ArticleDOI
TL;DR: It is proposed that the symbolsdrm anddra be used to denote the structural genes for deoxyribomutase and de oxygenriboaldolase respectively, which provide a method for discriminating between different classes oftlr mutants ofEscherichia coli K12, which cannot utilize deoxy ribose as a carbon source.
Abstract: Thymineless mutants ofSalmonella typhimurium which are able to grow with low added concentrations of thymine (20 μM) fall into two classes on the basis of growth on deoxyribose as sole carbon source. Those which can grow are deoxyribomutase negative and those which cannot are deoxyriboaldolase negative. The former class are inhibited by deoxynucleosides and this provides a method for discriminating between different classes oftlr mutants ofEscherichia coli K12, which cannot utilize deoxyribose as a carbon source. It is suggested that the sensitivity of deoxyriboaldolase negative strains is due to the accumulation of deoxyribose-5-phosphate. The data also indicate that deoxyribose-5-phosphate is the inducer of thymidine phosphorylase. It seems that one or both of the deoxyribose phosphates is the toxic compound, and that reversal of inhibition by ribonucleosides is due to inhibition of the enzymes catalysing their formation from deoxynucleosides. We propose that the symbolsdrm anddra be used to denote the structural genes for deoxyribomutase and deoxyriboaldolase respectively.

Journal ArticleDOI
01 Jun 1968
TL;DR: The ‘M.I.T. rule’ and two Lyapunov synthesis methods of design are critically reviewed and the input modification scheme of Grayson and Parks' method for the determination of parameter-adjusting feedback loops is reviewed.
Abstract: The ‘M.I.T. rule’ and two Lyapunov synthesis methods of design are critically reviewed. The latter are the input modification scheme of Grayson and Parks' method for the determination of parameter-adjusting feedback loops. For large inputs such methods are unsatisfactory: this is demonstrated by root locus plots for the step response of a second-order system with adaptive gain.A Lyapunov synthesis procedure is proposed which is a composite solution. The feedback loops of Parks are employed but an input modification signal is superimposed. This can be conveniently chosen from existing signals to add a fourth order negative definite term to V, thus promoting a greater degree of stability for large inputs. Results from an analogue computer study are included. The method is general in application.


Journal ArticleDOI
TL;DR: It is suggested that either the cytoplasmic membrane of the Ref-II mutants undergoes some change in properties at 30 °C, rendering the cells refractory to E2 or that the mutants may produce an altered protein (at30 °C) the function of which is normally involved in the transmission of the effect of the adsorbed colicin to its lethal site of action.

Patent
26 Jul 1968
TL;DR: In this paper, a patterning mechanism for a circular knitting machine having a stack or series of rotary discs, or other peripheral formations is presented and is co-operable with a single patterning butt on each of a series of presser elements.
Abstract: A patterning mechanism for a circular knitting machine having a stack or series of rotary discs, or other peripheral formations. These peripheral formations are present or absent according to a predetermined pattern and are co-operable with a single patterning butt on each of a series of presser elements which each have a series of height selection butts. These height selection butts cause the presser elements to raise and lower so that the patterning butts of the presser elements are co-operable with selected discs or rows of the stack or series characterized by at least one height selection station for the presser members. Each height selection station includes at least a butt rising cam and a butt lowering cam each mounted on a separate operating element for movement in or out of the path of height selection butts on the presser members. Latch means or spring loaded pivotally mounted latching member is provided for latching the operating element in the operative position with its cam in the path of the height selection butts until positive release of the latch means. The latching member has a shoulder which engages a selected bell crank, which bell crank actuates a selected operating element, when the selected bell crank is in a forward position to maintain the selected operating element in the operative position. When the latching member is released, a second selected bell crank becomes operative and forces the latch out of engagement with the first selected bell crank, thus allowing the first selected bell crank to retract from the selected operating element which in turn allows the opeating element to retract from the operative position.

Journal ArticleDOI
TL;DR: In this paper, it was shown that electron mobility in the ultra-pure liquid is predominantly electronic and that both electrons and holes propagate by an intermolecular hopping mechanism, and that the steady dark current is ohmic, although on application of the field the initial current is injected under space-charge limited conditions.
Abstract: The transport of generated charge carriers in sulphur has been investigated by drift mobility techniques during the melting of single crystals (at similar 114 °c) and also in the liquid prepared from molten granules of ultra-pure (6N) or laboratory reagent sulphur. The discussion of the results leads to the conclusion that in the ultra-pure liquid the transport is predominantly electronic and that both electrons and holes propagate by an intermolecular hopping mechanism. For electrons the transport mechanism is the same as in the solid, but during melting the intermolecular overlap energy drops by about a factor of 5, leading to an electron mobility μe = 10-4 cm2 s-1 v-1 at 120 °c. The hole conduction, which takes place in a small-polaron band in the solid, changes to a hopping transport upon melting. The magnitude and temperature dependence of μh is then very similar to that of μe. These results are discussed in the light of Holstein's small-polaron theory. Experiments on less pure liquid specimens show additional features which appear to arise from the ionization of impurity molecules during the transit of the generated carriers. Above 160 °c a change in the temperature dependence of μe and μh occurs, connected with the break-up and polymerization of the S8 ring molecules. The efficiency of photogeneration in the liquid is lower than in the solid, but its spectral dependence is substantially the same. The steady dark current in the ultra-pure liquid is ohmic, although on application of the field the initial current is injected under space-charge-limited conditions. The different steady dark current behaviour of the impure liquid has been attributed to the formation of heterocharge layers near the electrodes.

Journal ArticleDOI
01 Nov 1968
TL;DR: The CEGB requirement for alarm analysis is detailed, and different methods used are reviewed, covering the different display and printing facilities available from the computer system at Wylfa.
Abstract: The CEGB requirement for alarm analysis is detailed, and different methods used are reviewed. The method used at Wylfa is described, covering the different display and printing facilities available from the computer system. Both the alarm and data facilities are described. A brief account of the computer equipment is given, and the methods of alarm detection are described. The organisation of the computer program is described, with tables of the fast-store and drum-store use. The system is now operational for station-plant commissioning, prior to delivery of power scheduled for 1969.


Journal ArticleDOI
TL;DR: Thyroxine treatment resulted in increased swimming and jumping, an altered swimming pattern, and decreased oxygen consumption, and the respiratory quotient indicated normal carbohydrate metabolism.


Journal ArticleDOI
TL;DR: In this paper, the long and short-term effects of exposure to high intensity noise are discussed and individual differences in the effects of noise are also discussed, and it is shown that on some tasks noise exerts a beneficial effect and this would appear to result from an increase in the level of arousal.

Journal ArticleDOI
TL;DR: Electron transport particles derived from cells grown under nitrogen-fixing conditions and on glutamate or ammonium medium contained high concentrations of ubiquinone, flavoprotein and cytochromes c4 + c5, b1, a1 and a2, but in particles from cells growing on urea medium the cytochrome b1 was only 55–70% reduced in the anaerobic state.