Showing papers by "University of Birmingham published in 1976"
TL;DR: A technique is described which enables the distribution of discomfort in the body, and its change during the work poriod, to be recorded to indicate points of inadequate man-machine compatibility as well as permitting the evaluation of the effectiveness of machine designs.
Abstract: A technique is described which enables the distribution of discomfort in the body, and its change during the work poriod, to he recorded. The recorded data indicate points of inadequate man-machine compatibility as well as permitting the evaluation of the effectiveness of machine designs. When used in conjunction with moasures of production performance the technique provides direct evidence of the benefits of orgonomic changes. Its use is illustrated in relation to a study of spot welders.
946 citations
TL;DR: The changes which follow cross reinnervation of mammalian fast and slow twitch muscles may reflect a capacity of skeletal muscle to respond adaptively to different functional requirements.
Abstract: The changes which follow cross reinnervation of mammalian fast and slow twitch muscles may reflect a capacity of skeletal muscle to respond adaptively to different functional requirements. This interpretation is supported by experiments in which long-term electrical stimulation was used both to reproduce and to oppose the effects of cross reinnervation.
587 citations
TL;DR: The regulation of contractile activity in cardiac muscle by changes in the intracellular Ca2+ concentration involves the regulatory protein system, consisting of tropomyosin and the troponin complex that is located in the I filament.
Abstract: THE regulation of contractile activity in cardiac muscle by changes in the intracellular Ca2+ concentration involves the regulatory protein system, consisting of tropomyosin and the troponin complex that is located in the I filament. Although the regulatory protein system of cardiac muscle is essentially similar in function to that of skeletal muscle, the components differ in the two tissues. Cardiac tropomyosin consists principally of α subunits, whereas the skeletal protein is composed of α and β subunits1. Troponin I, troponin C and troponin T are all specific for cardiac muscle in that they have different chemical and immunochemical properties from the corresponding skeletal muscle proteins2–4. In addition, cardiac troponin I and cardiac troponin C have been shown to have different amino acid sequences from their skeletal muscle counterparts3,5.
373 citations
TL;DR: In this paper, a mass-selected, low-energy, positive ion beam, derived from a gas-discharge source in conjunction with a quadrupole mass filter, is injected into a flowing gas.
337 citations
323 citations
TL;DR: In this article, a spin model of a spin glass is solved in the limit of infinite-ranged interactions with a gaussian probability distribution, and it is shown that for suitable values of the mean and variance of the distribution, the model can display either spin glass or ferromagnetic ordering.
Abstract: A spherical model of a spin glass is solved in the limit of infinite-ranged interactions with a gaussian probability distribution. It is shown that for suitable values of the mean and variance of the distribution, the model can display either spin glass or ferromagnetic ordering; identical results obtain using the n → 0 method. The distribution of internal fields is shown to be gaussian.
292 citations
TL;DR: It is concluded that only low frequency activation of fast muscles brings about a transformation of the muscle fibres towards a slow type and that the first noticeable change is an increase in the capillary density.
Abstract: When rabbit fast muscles were chronically stimulated at a frequency naturally occurring in nerves to slow muscles (10 Hz), there was a transformation towards a slow muscle type such as an increase of capillary density, increased activity of the oxidative enzyme, succinic dehydrogenase, and a decrease of muscle fibre diameters. After 28 days the intensity and distribution of SDH and the capillary density were similar to those of soleus. The increases in capillary density preceded the changes in activity of SDH; there was a significantly greater capillary/muscle fibre ratio and number of capillaries/mm2 in muscles stimulated for only 4 days at which time no change could be detected in SDH. These changes were induced by slow frequency stimulation only, and not by an overall increase of activity. Stimulation of fast muscles for 4 days at a higher frequency naturally occurring in the nerves to fast muscles (short bursts of tetani), with the same total number of stimuli as that used in slow frequency stimulation did not produce any changes in capillary density, activity of SDH or contraction times. No changes were observed in either fast or slow muscles stimulated with short bursts of tetani (and lower total number of impulses) up to 28 days. Activation of fast muscles at 5 Hz continuously or 10 Hz intermittently also caused an increase in capillary density. It is therefore concluded that only low frequency activation of fast muscles brings about a transformation of the muscle fibres towards a slow type and that the first noticeable change is an increase in the capillary density.
248 citations
TL;DR: In these experiments, it seemed that microvesicles budded off from the microvillus-like projections on the echinocytes, and were isolated and examined their composition and structure.
Abstract: WHEN the intracellular Ca2+ concentration of human red cells was increased by treatment of the cells with A23187, a divalent cation ionophore, they changed shape from discocyte to echinocyte1–3 and the 1,2-diacylglycerol content of their membranes was increased2–4. In these experiments it seemed that microvesicles budded off from the microvillus-like projections on the echinocytes2,3. We have now isolated the microvesicles and examined their composition and structure.
227 citations
TL;DR: A series of defined peptides which span the complete sequence were produced from troponin I isolated from white skeletal muscle of the rabbit, and the most active inhibitor, peptide CN4, was 45-75% as effective as tropon in I when compared on a molar basis.
Abstract: 1. A series of defined peptides which span the complete sequence were produced from troponin I isolated from white skeletal muscle of the rabbit. 2. Two peptides, CF1 (residues 64-133) and CN4 (residues 96-117) inhibited the Mg2+-stimulated adenosine triphosphatase of desensitized actomyosin. This inhibition was potentiated by tropomyosin and the Mg2+-stimulated adenosine triphosphatase of desensitized actomyosin. This inhibition, unlike that of troponin I and peptides derived from it, was not potentiated by tropomyosin. 4. The most active inhibitor, peptide CN4, was 45-75% as effective as troponin I when compared on a molar basis. The inhibitory peptide, CN4, and also whole troponin I were shown by affinity chromatography to interact specifically with actin. 5. A strong interaction with troponin C was demonstrated with peptide CF2 (residues 1-47), from the N-terminal region of troponin I. Somewhat weaker interactions were shown with peptides CN5 (residues 1-21) and with the inhibitory peptide CN4. 6. The significance of these interactions for the mechanisms of action of troponin I is discussed.
224 citations
TL;DR: Findings on paired-associate learning differ in autistic and amnesic subjects, but findings on recall, recognition and cued recall are comparable.
Abstract: Autistic children were compared with control children on tasks in which retention was tested by different methods. In three tests of recall, using named pictures, written words and spoken words as test stimuli, autistic children were impaired in comparison with age-matched normal children and with controls matched for verbal and non-verbal ability. In one test of forced-choice recognition of pictures, autistic children were impaired in comparison with ability-matched controls. In three tests of cued recall, using named pictures, written words and spoken words as test stimuli, and acoustic, graphemic and semantic cues, autistic children were not impaired in comparison with normal age-matched controls. In one test of paired-associate learning using non-related word pairs as test stimuli autistic children were not impaired in comparison with normal age-matched controls. These experimental paradigms were similar to some that have been used to investigate the amnesic syndrome in man. Thus findings on paired-associate learning differ in autistic and amnesic subjects, but findings on recall, recognition and cued recall are comparable. A possible parallel between autism and amnesia is discussed.
221 citations
TL;DR: If it is to be shown unequivocally that it is rate of operant responding which determines the behavioral effects of drugs, procedures are needed in which other varibles such as reinforcement frequency are more adequately controlled.
Abstract: It has been claimed that the effects of amphetamines on schedule-controlled behavior depend to a large extent on the rate of responding in control conditions. A review of the literature shows that there is considerable support for this hypothesis if the behavior is not suppressed by aversive procedures, is not under the control of powerful external stimuli or is not occurring very infrequently. The extension of a rate-dependency hypothesis to the effects of other drugs has less empirical support, however. It is argued that many of the procedures used for studying rate-dependent drug effects do not provide critical tests of the hypothesis. If it is to be shown unequivocally that it is rate of operant responding which determines the behavioral effects of drugs, procedures are needed in which other varibles such as reinforcement frequency are more adequately controlled.
TL;DR: The agreement between zygosity diagnosis in twins by reference to the twins' own answers to written questions and diagnosis based on an objective assessment of Zygosity by blood-typing is studied for 178 pairs of same sex twins as mentioned in this paper.
Abstract: The agreement between zygosity diagnosis in twins by reference to the twins' own answers to written questions and diagnosis based on an objective assessment of zygosity by blood-typing is studied for 178 pairs of same sex twins. Seventy-two female and 106 male twin pairs answered two questions concerning their similarity in appearance and frequency of confusion in childhood, and were blood-grouped using up to 23 different antisera. Of those pairs concordant for all markers and diagnosed as MZ, 98% agreed that they were confused in childhood and that they are alike in physical appearance. Only 55% of those pairs discordant for at least one marker and classified as DZ agreed that they were never confused and are not alike in appearance. The replies of the remaining 45% are spread over all the other combinations of responses. If all twins who agree that they were confused in childhood and are alike in appearance were to be classified as MZ on the basis of the questionnaire alone, and all others as DZ, the diagnoses of only seven pairs out of the total 178 (3–9%) would disagree with those based on blood group data.
TL;DR: The radiosensitivity of patients with ataxia telangiectasia is observed at the chromosomal level in blood lymphocytes X irradiated at different stages of the cell cycle and for the same range of doses as the authors' survival experiments, consistent with the hypothesis that there is a defect in some form of DNA repair in these patients.
Abstract: THE radiosensitivity of patients with ataxia telangiectasia (AT) has been indicated by in vivo studies1–3 and in vitro studies on skin fibroblasts4. We present data here to show that this radiosensitivity is observed at the chromosomal level in blood lymphocytes X irradiated at different stages of the cell cycle and for the same range of doses as our survival experiments4. Our results are consistent with the hypothesis that there is a defect in some form of DNA repair in these patients. From the observation of the types of chromosome aberrations seen in AT lymphocytes after irradiation at G0/early G1, we propose a mechanism for the origin of these aberrations, based on the premise that the G0/early G1 chromosome contains a single DNA double helix, in which one polynucleotide chain can be damaged independently of the other.
TL;DR: The growth of Purkinje cell dendritic trees in the cerebellum of the rat was studied over the first 50 days of life, using the technique of network analysis and the Golgi-Cox impregnation method to show that a growth spurt occurred from the 10th to 30th day post partum and involved the production of a massive number of branches of fairly constant length.
TL;DR: The genetical components of family means and variances, simply and reliably estimated in the first few generations of any breeding programme initiated from a cross between two inbreeding lines, are all that is required to predict the distribution of the inbred lines that can be derived by single seed descent from the F2 of such a cross.
Abstract: The genetical components of family means and variances, simply and reliably estimated in the first few generations of any breeding programme initiated from a cross between two inbred lines, are all that is required to predict the distribution of the inbred lines that can be derived by single seed descent from the F2 of such a cross. We can, therefore, determine the probability of obtaining inbreds that fall outside of the parental range or of exceeding the F1 if it shows heterosis, by any amount we care to specify. While epistasis, genotype × environmental interactions and linkage may at first sight appear to seriously disturb any such prediction they can all be accommodated. In practice only epistasis is expected and found to produce disturbances of a sufficient magnitude to justify making allowance for its presence in making these predictions. This is because it leads to asymmetry in the distribution of derived inbreds relative to the initial inbred parental means. The predictive power of this new approach is demonstrated on two complete breeding cycles, each initiated by a cross between two pure-breeding varieties of Nicotiana rustica and culminating in the production of over 100 recombinant, pure-breeding lines. The ability of the analysis to discriminate between two crosses on the basis of their probabilities of producing inbred lines that fall outside of their parental range is also demonstrated. By using analyses of this kind there is no reason why we need ever go beyond the F2 of an inbreeding programme without a fairly clear idea of the outcome.
TL;DR: It is reported here that modulator protein possesses troponin C-like activity in Ca2+-regulated actomyosin systems from skeletal muscle and is as effective in the presence of trop onin I and tropomyos in skeleta muscle as it is in the absence of these components.
TL;DR: Results extend to man recent demonstrations that the satisfying power of a foodstuff is in part acquired by association of its sensory characteristics with some consequence of ingesting the nutrients which are consistently taken with or in that food.
Abstract: Lean male and female subjects who had been taking their meals as usual were given a 100 ml drink of starch immediately before a sandwich lunch. In the training phase, 65 per cent starch was given before lunches which included a yoghurt‐based dessert of one flavour and 5 per cent starch was given before another flavour. Subjects who initially ate lunches of similar size following the two drinks began after several pairings to take larger lunches following dilute starch than following concentrated starch. In extinction tests, identical 35 per cent starch drinks were given before lunches including desserts of either flavour. Lunches including the flavour hitherto paired with dilute starch remained larger than lunches including the other flavour, at least initially in extinction. Some of the difference in intake occurred in the dessert itself. None was attributable to differences in the early stage of the lunches. These results extend to man recent demonstrations that the satisfying power of a foodstuff is in part acquired by association of its sensory characteristics with some consequence of ingesting the nutrients which are consistently taken with or in that food. This consequence may be rapid intestinal absorption of glucose during or shortly after sensory input. The nature of the intake‐ suppressing response remains to be determined.
TL;DR: A model is developed to specify the environmental effect of one sibling on another for a polygenic trait that is detectable in principle and the approach is illustrated with twin data relating to psychoticism.
Abstract: A model is developed to specify the environmental effect of one sibling on another for a polygenic trait. Such effects are detectable in priniciple and the approach is illustrated with twin data relating to psychoticism. The relationship between the model and those employed in the treatment of kin selection is indicated.
TL;DR: The results for the He++N2 reaction agree with the previously established branching ratio and considerable differences are apparent between the product distributions obtained and those previously reported and an explanation is attempted.
Abstract: The reactions of He+ ions with N2, O2, CO2, and CH4, and of C+ and N+ ions with O2 are presented. The measurements were carried out in the SIFT apparatus (selected ion flow tube), which involves the injection of a mass-selected positive-ion beam into a flowing neutral gas into which a reactant gas is introduced at a position downstream in the flow. Data acquisition and analysis are made by the flowing afterglow technique. The results for the He++N2 reaction agree with the previously established branching ratio. For the other reactions, considerable differences are apparent between the product distributions obtained and those previously reported and an explanation is attempted. A brief discussion of the reaction mechanism is presented for each reaction in the light of the determined product distributions, and the anticipated development of the SIFT technique for ion-molecule reaction mechanisms is outlined.
TL;DR: In this article, the Fraunhofer absorption lines for potassium and sodium on the Sun were compared with the corresponding lines in the laboratory using a resonant optical scattering method, and the observed shifts between the Sun and laboratory lines may be interpreted in terms of the gravitational redshift (GRS), motion of the laboratory relative to the Sun, and oscillatory terms which may be related to oscillations of the Sun.
Abstract: The Fraunhofer absorption lines for potassium and sodium on the Sun are compared with the corresponding lines in the laboratory using a resonant optical scattering method. The observed shifts between the Sun and laboratory lines may be interpreted in terms of the gravitational redshift (GRS), motion of the laboratory relative to the Sun and oscillatory terms which may be related to oscillations of the Sun.
TL;DR: In this paper, the critical behavior of one-dimensional ferromagnetic chains with isotropic long-range interactions between $n$-component spins is investigated near the critical range of ${r}^{\ensuremath{-}2}$.
Abstract: The critical behavior of one-dimensional ferromagnetic chains with isotropic long-range interactions between $n$-component spins is investigated near the critical range of ${r}^{\ensuremath{-}2}$ Different formulations of the renormalization group are used for $ng1$ and $n=1$ It is shown that the behavior is quite different in the two cases, with very close analogies to the short-range problem near two dimensions Critical exponents are calculated to first order
TL;DR: Topological type analysis revealed that the trees had arisen in a manner indistinguishable from terminal dichotomous branching and that the 'weep-willow' pattern was produced by a deviation of branching from a purely random form.
TL;DR: An independent approach is pursued and the successful immobilisation of cells on the hydroxides (hydroxyoxides) of titanium (IV) and zirconium by a chelation process is reported.
Abstract: THE immobilisation of enzymes by attachment to water-insoluble materials has received considerable attention recently1, both for academic reasons and for possible industrial applications. A logical extension of this approach, especially where multi-stage enzymic reactions are being considered, is the immobilisation of microorganisms, which are often the source of many enzyme preparations. The advantages of such an approach are immediately obvious. The tedious and time consuming procedures for enzyme extraction and purification are instantly eliminated, cofactors and coenzymes are readily at hand, the cellular enzymes are often organised into the requisite metabolic pathways and problems associated with enzyme instability may also be avoided. Furthermore, the use of immobilised cells would avoid the problem in industrial processes of separating the product from the enzyme. The immobilisation of cells by the standard glutaraldehyde procedure, however, causes their decease, and entrapment in polyacrylamide gel is commonly used instead to achieve immobilisation2,3. This method produces a minimum of interaction between the microbial cell and the insoluble matrix, thus maximising the probability of the cell's survival. On the other hand, the availability of the cell to any intended substrate is seriously reduced, since it can reach the cell only by diffusion. An alternative approach of immobilising cells on collagen, by the formation of a stable network of multiple ionic (salt) linkages, hydrogen bonds and Van der Waals' interactions has been successful4. We have now pursued an independent approach and report here the successful immobilisation of cells on the hydroxides (hydroxyoxides) of titanium (IV) and zirconium (IV) by a chelation process.
TL;DR: For optimum lipid mobilization haemolymph protein and calcium ions were required, and the amount and time course of release were dependent on the hormone concentration, and a synergistic effect of theophylline with hormone was found.
12 Oct 1976-Philosophical transactions - Royal Society. Mathematical, physical and engineering sciences
TL;DR: In this paper, the usefulness of magnetic and seismic anisotropy in fabric studies is investigated. But the authors focus on the magnetic anisotropic properties of fabric and do not consider the seismic properties.
Abstract: Anisotropy in any physical property of a material implies that the response of the material to an applied field depends on the direction in which the field is applied. In single crystals anisotropy may be an intrinsic property (Nye I964), but in rocks it is usually determined by the integrated effects of many fabric elements, which may interact in complex ways. The specification of an anisotropic property necessarily implies that on the scale of interest the body may be treated as homogeneous. Anisotropic properties are important in geology in two distinct, though related, ways. Firstly, a knowledge of anisotropy is important for a full understanding of geological processes - the influence of rheological anisotropy in deformation is an obvious example. Secondly, measurement of anisotropy may be used to provide information about the fabric of rocks. In comparison with other methods of studying fabric, the relative usefulness of any anisotropic property is determined by a balance between the ease and speed with which it can be measured, the extent to which the contribution of different fabric elements can be resolved and the amount of information (necessarily limited by symmetry) which is carried by the anisotropic property. This paper is principally concerned with the usefulness of magnetic (?2) and seismic (?3) anisotropy in fabric studies; other anisotropic properties will be considered briefly in ?4. In many ways magnetic and seismic anisotropy represent opposite extremes. The former is limited to measurements on the scale of a hand sample and for such specimens measuring procedures are well established. Since magnetic anisotropy is one of the least complex of the anisotropic properties of rocks, in terms of the multiplicity of fabric elements involved, its analysis and its consequent applicability and limitations are relatively well understood. By contrast seismic anisotropy is, at the outset, a more complicated phenomenon. It too may be measured on the laboratory scale, but the possibility that excites greater interest is that of in situ determination of anisotropy on a much larger scale, on regions of the crust and upper mantle which are inaccessible to direct observation, but of great interest tectonically. The physical constraints
TL;DR: The planning, execution and preliminary results of a major Anglo-German explosion seismic project are presented in this, paper I of a series as discussed by the authors, which was planned as a reversed 1000 km line between two major sea-shot points off Cape Wrath in Scotland and one in the English Channel; additional sea-shots and intermediate land-shots were fired to give reversed and overlapping crustal coverage along the line.
Abstract: Summary
The planning, execution and preliminary results of a major Anglo-German explosion seismic project are presented in this, paper I of a series. This Lithospheric Seismic Profile in Britain (LISPB) was planned as a reversed 1000 km line between two major sea-shot points off Cape Wrath in Scotland and one in the English Channel; additional sea-shots and intermediate land-shots were fired to give reversed and overlapping crustal coverage (to 180–400 km distance) along the line. In all, 29 shots were fired and 60 mobile magnetic tape stations recorded three-components of ground‘motion. The resulting 14 crustal and three long-range profiles have observations at intervals of typically 2–4 km. Recordings have been digitized and four examples of filtered, computer-plotted record sections are presented to illustrate data quality. In a preliminary analysis, phase correlations are discussed and some models presented; the latter especially are more relevant to future interpretations than to geological or tectonic problems. However, significant variations in crustal thickness and in the nature of the crust-mantle transition do seem to occur beneath the British Isles.
TL;DR: The results showed that both treatments led to significant improvements in the patients' social lives, which, in the case of social skills training were maintained at 6 months follow-up, which led to suggestions made for further research in this area.
TL;DR: A sequence of intensely sheared, polyphasally deformed turbidites and pillow lava rocks of possible late Paleozoic or Triassic age, exposed along western Alexander Island, is tentatively interpreted as a trench assemblage accreted during an early stage of subduction as discussed by the authors.
Abstract: Three main Upper Jurassic–Cretaceous tectono-stratigraphic units recognized in Palmer Land and Alexander Island are comparable with assemblages formed (1) in an ensialic volcanic arc (Upper Jurassic Volcanic Group), (2) in a forearc or intra-arc marine basin (Fossil Bluff Formation), and (3) in a back-arc marine basin (Crabeater Point sediments and Latady Formation), possibly representing a proto–Weddell Sea. A sequence of intensely sheared, polyphasally deformed turbidites and pillow lava rocks of possible late Paleozoic or Triassic age, exposed along western Alexander Island, is tentatively interpreted as a trench assemblage accreted during an early stage of subduction. There is a close correlation between these units and the approximately coeval island-arc-marginal basin system of the southern Andes and South Georgia.