Showing papers by "University of Birmingham published in 1969"
330 citations
TL;DR: In this paper, partial derivatives of a matrix function with respect to the elements of the argument matrix are identified. And three definitions of partial derivatives matrices are used, to be denoted by D 1, D 2 and D 3.
Abstract: Matrix differentiation, the procedure of finding partial derivatives of the elements of a matrix function with respect to the elements of the argument matrix, is the subject matter of this paper. The method followed here amounts to linking the differentials of the matrix function and the argument matrix, and then identifying matrices of partial derivatives. The basic assumption made is mathematical independence of the elements of the argument matrix. Matrix functions are divided into two categories: Kronecker matrix products and non-Kronecker (= ordinary) matrix products. Three definitions of partial derivatives matrices are used, to be denoted by D 1, D 2 and D 3 in this abstract. D 2 and D 3 are applied to Kronecker products, D 1 is applied to ordinary products. This is a matter of efficiency only. D 1 is developed first. Transforming matrices into column vectors turns out to be very convenient. D 2 and D 3 are developed then. D 3 is a generalisation of D 1.
291 citations
TL;DR: It is proposed that the control of the diglyceride concentration of locust haemolymph during flight is mediated, at least in part, by a peptide hormone released from the corpora cardiaca.
268 citations
TL;DR: Replacement therapy instituted from the time of thyroidectomy reversed completely the reduction in myelin deposition as assessed by the amount of cerebrosides per unit weight of cerebrum.
195 citations
188 citations
TL;DR: Evidence is presented indicating that the ability of tropomyosin preparations to restore relaxing-protein-system activity to the troponin complex and their inhibitory effect on the Ca(2+)-stimulated adenosine triphosphatase activity of desensitized actomyOSin are two properties of different stability to preparative procedures and tryptic digestion.
Abstract: 1. A method involving isoelectric precipitation and chromatography on SE-Sephadex (sulphoethyl-Sephadex) is described for the preparation of the troponin complex free of tropomyosin from low-ionic-strength extracts of natural actomyosin and myofibrils. 2. Purified troponin complex required tropomyosin to inhibit the Mg 2+ -stimulated adenosine triphosphatase activity and superprecipitation of desensitized actomyosin in the presence of ethanedioxybis(ethylamine)tetra-acetate. An upper limit of 35000 for the ‘molecular weight’ of the troponin complex was derived from the amounts required to bring about 50% of the maximum inhibition of the Mg 2+ -stimulated adenosine triphosphatase activity of desensitized actomyosin of known concentration. 3. In the presence of dissociating reagents the troponin complex could be dissociated into inhibitory and Ca 2+ -sensitizing factors, which could be isolated separately on SE-Sephadex. The inhibitory factor inhibited the Mg 2+ -stimulated adenosine triphosphatase activity and superprecipitation of desensitized actomyosin independently of the concentration of free Ca 2+ in the medium. 4. The Ca 2+ -sensitizing factor changed its electrophoretic mobility on polyacrylamide gel in the presence of ethanedioxybis(ethylamine)tetra-acetate. It formed a complex with the inhibitory factor at low ionic strength and the original biological activity of the troponin complex could be restored on mixing the inhibitory factor with the Ca 2+ -sensitizing factor in the ratio of about 3:2. 5. Evidence is presented indicating that the ability of tropomyosin preparations to restore relaxing-protein-system activity to the troponin complex and their inhibitory effect on the Ca 2+ -stimulated adenosine triphosphatase activity of desensitized actomyosin are two properties of different stability to preparative procedures and tryptic digestion. This suggests that the relaxing protein system of muscle may contain another as yet uncharacterized component.
186 citations
185 citations
TL;DR: The emotional stress of being brought to the operating theatre and the stress of surgery seem to be more important than anaesthesia in causing a rise in blood sugar and plasma FFA and a corresponding fall in levels of plasma insulin.
Abstract: SUMMARY The effects of emotional stress, nitrous oxide and halothane anaesthesia, a 1-minute period of hypoxia, and surgery, on the blood sugar, plasma free fatty acids (FFA) and insulin were investigated. The emotional stress of being brought to the operating theatre and the stress of surgery seem to be more important than anaesthesia in causing a rise in blood sugar and plasma FFA. There was a corresponding fall in levels of plasma insulin. The infusion of Phentolamine in two patients did not prevent the failure of insulin response to injected glucose during surgery. The clinical significance of this temporary state of glucose intolerance is discussed.
171 citations
TL;DR: A general method of detecting additive, dominance and epistatic variation for metrical traits II and application to inbred lines is proposed.
Abstract: A general method of detecting additive, dominance and epistatic variation for metrical traits II. Application to inbred lines
159 citations
TL;DR: Unilateral stereotaxic lesions were made in the superior colliculus, the inferior colliculi, the red nucleus or the reticular formation of the midbrain of rats.
Abstract: Unilateral stereotaxic lesions were made in the superior colliculus, the inferior colliculus, the red nucleus or the reticular formation of the midbrain of rats. The descending fibers from these sites were studied using the method of Nauta ('57).
One crossed and two uncrossed tracts descend from the superior colliculus. These tracts terminate mainly in the reticular formation of the medulla oblongata. Only a small number of tecto-spinal fibers were found. These were confined to the upper contralateral cervical segments of the cord. The tecto-spinal fibers terminate on cells in the ventral gray matter of the cord, corresponding in position to those in Rexed's lamina VIII in the cat.
One uncrossed descending tract passes from the inferior colliculus and terminates in the reticular formation of the medulla oblongata. No fibers were contributed to the tecto-spinal tract by the inferior colliculus.
Rubro-spinal fibers decussate completely in the ventral tegmental decussation and descend in the lateral funiculus of the cord into lumbar segments and on interneurons which correspond in position to those in Rexed's laminae V and VI in the cat.
From the reticular formation of the midbrain, ipsilateral fibers course in the ventral funiculus of the cord, descending to the ninth or tenth thoracic segments. These fibers terminate on cells corresponding in position to those in Rexed's lamina VIII in the cat. Considerable preterminal degeneration, mainly ipsilateral, was found in the brain stem of the animals with lesions in the midbrain reticular formation.
The findings are discussed in relation to what has been reported previously in the rat, and in other animals.
146 citations
TL;DR: The results obtained indicated that mitochondria were capable of synthesizing phosphatidate, though this activity was only about one-third of the total homogenate activity.
Abstract: 1. After conventional fractionation of rat liver homogenates in 0·88m-sucrose the mitochondrial fraction was subjected to short-term water lysis followed by separation of the resulting membrane preparations. 2. Phosphatidate formation was measured in all subcellular fractions and subfractions and was compared with the distribution of succinate dehydrogenase, monoamine oxidase, rotenone-insensitive NADH cytochrome c reductase, arylsulphatase, urate oxidase, arylesterase and glucose 6-phosphatase. 3. The results obtained indicated that mitochondria were capable of synthesizing phosphatidate, though this activity was only about one-third of the total homogenate activity. 4. Mitochondrial phosphatidate formation was located predominantly in the outer mitochondrial membrane. Although this membrane preparation was found to be significantly contaminated by the microsomal fraction, this contamination was estimated to account for not more than about 20% of the total phosphatidate formation observed in preparations of outer mitochondrial membrane.
TL;DR: An improved general formulation for finite time horizon, stochastic, dynamic programming problems is developed and the cases of finite and infinite planning horizons and discounted and undiscounted costs are discussed.
Abstract: In the repair limit replacement method when an item requires repair it is first inspected and the repair cost is estimated. Repair is only then undertaken if the estimated cost is less than the "repair limit". Dynamic programming methods are used in this paper as a general approach to the problem of determining optimum repair limits. Two problems are formulated and the cases of finite and infinite planning horizons and discounted and undiscounted costs are discussed. Methods are given for allowing for equipment availability and for the introduction of new types of equipment. An improved general formulation for finite time horizon, stochastic, dynamic programming problems is developed.
TL;DR: The Dimlington Silts as discussed by the authors are a series of laminated silts and sands, exposed near the foot of Dimlington cliff (TA 391217) and have been interpreted as interglacial deposits of the Wurm (Weichsel) glaciation.
Abstract: THE Dimlington Silts are a series of laminated silts and sands, exposed near the foot of Dimlington Cliff (TA 391217). They occupy hollows on the surface of the Saale (Basement) till, and are overlain by the Weichsel (Drab) till and have been interpreted1 not as interglacial deposits but as interstadial deposits of the Wurm (Weichsel) glaciation, with the overlying Drab, Purple and Hessle tills belonging to the Main Wurm (that is, Upper Pleniglacial2).
TL;DR: It is suggested that the acute pulmonary hypertension seen in patients with acute respiratory failure secondary to chronic bronchitis is due primarily to pulmonary vasoconstriction resulting from hypoxia.
Abstract: Eight patients with acute respiratory failure secondary to chronic bronchitis were studied for up to 5 consecutive days following admission; cardiac output and intravascular pressures, blood volume, arterial blood gas tensions, and body weight were measured. These observations were also compared with further measurements made some weeks later just before the patient was discharged. The effects of oxygen and acetylcholine on the pulmonary circulation were also studied. Pulmonary arterial pressure was raised in all patients during their acute illness and had fallen substantially after recovery. The pulmonary arterial pressure throughout the study correlated directly with the arterial carbon dioxide and inversely with the arterial oxygen tensions. The inhalation of 24% and 28% oxygen and the infusion of acetylcholine into the pulmonary artery resulted in a fall in pulmonary arterial pressure, often to levels close to those subsequently seen after recovery from the acute illness. No significant change in cardiac output was observed. It is suggested that the acute pulmonary hypertension seen in these patients is due primarily to pulmonary vasoconstriction resulting from hypoxia.
TL;DR: In this article, the authors investigated the mechanism causing extrinsic faults to grow into a silicon wafer during thermal oxidation using annealing experiments on thin electron microscope foils.
Abstract: The mechanism causing extrinsic faults to grow into a silicon wafer during thermal oxidation has been investigated by annealing experiments on thin electron microscope foils. The defects grow on annealing in air at 1100°C and shrink on annealing in vacuo at the same temperature; this behaviour is explained in terms of the diffusion of vacancies between defect and surface. The sense of this flow is dependent on the vacancy concentration in equilibrium with the surface which is reduced to approximately 0·8 of the bulk equilibrium value because the vacancies are annihilated by the inward-growing oxide. During oxidation the faults emit vacancies to the surface, causing fault growth, whereas the vacancy flow is reversed on annealing in vacuo. The activation energy for fault shrinkage has been determined to be 2·1 ev, which is consistent with pipe diffusion along the core of the bonding Frank dislocation. The shrinkage rate of these faults at constant temperature is proportional to the equilibrium vaca...
TL;DR: Serum-levels of IgG, IgA, IgM, and Summary IgD have been determined in 110 patients with adult cœliac disease and compared with levels in 152 healthy controls; significant increases in IgA were found, and these seem to be related to the quantity of gluten ingested and to milk sensitivity.
TL;DR: The evidence presented accords with the view that certain cells which line the III ventricle of the brain and have prolongations extending to pituitary blood vessels, thus linking the cerebrospinal fluid and the blood system in the region of the pituitsary, may play a role in the regulation of pituitaries function and thereby constitute an important neuro-endocrine system.
Abstract: Certain cells lining a circumscribed area of the III ventricle of the rhesus monkey differ from those cells which constitute the characteristic ependymal lining of the brain. The specialized cells studied comprise a number of types which differ in their structure, ultrastructure and staining affinities; all demonstrate features which are generally associated with active secretion and/or absorption. A group of such cells, which form a limited area of the latero-ventral walls of the anterior hypothalamus, have long processes which extend to the walls of the blood vessels in the median eminence. The evidence indicates that many of these cells, here described as Type B or tanycyte cells, secrete their products into the primary capillary network of the pituitary portal system. Another group of cells, here described as Type C and $C'$ cells are found in a slightly more posterior position lining the floor of the ventricle; as yet there are no indications that these may secrete into blood vessels in the median eminence. Some of the specialized cells lining the III ventricle (Types B and C') showed changes in relation to reproductive activity: No such changes were observed in Type C cells nor in the characteristic ependymal cells (Type A) found elsewhere. Studies on normal and experimental male and female monkeys showed that Type B tanycyte cells differed in males and females and altered during the menstrual cycle in the female. Following ovariectomy these cells showed regressive changes but returned to a normal appearance after a single injection of oestradiol. In view of the close spatial relationship of the tanycyte ependyma to cells of the pars tuberalis it was interesting to note that pars tuberalis cells also altered in relation to the menstrual cycle. The evidence presented accords with the view that certain cells which line the III ventricle of the brain and have prolongations extending to pituitary blood vessels, thus linking the cerebrospinal fluid and the blood system in the region of the pituitary, may play a role in the regulation of pituitary function and thereby constitute an important neuro-endocrine system.
TL;DR: The association of measured intelligence with maternal age and birth order in a general population of children is determined mainly by differences between rather than within families, and the negative correlation between sibship size and intelligence cannot be attributed substantially to variation in intelligence.
Abstract: This article examines the relationhip of verbal reasoning scores recorded for 48913 Birminghan children born in 1950-1954 to birth order and maternal age. It is shown that the scores are negatively correlated with sibship size and positively with maternal age. It is concluded that the association of measured intelligence with maternal age and birth order in a general population of children is determined mainly by differences between rather than within families. Therefore the negative correlation between sibship size and intelligence cannot be attributed substantially to variation in intelligence according to birth order or maternal age within sibships. The population was divided according to occupation of fathers into 3 social groups. Since distribution of children by mothers age and birth order is a distribution by social class the relation of scores to the 2 variables in a population of births is largely a reflection of the social class difference.
TL;DR: The distribution of radioactivity in the urine and faeces of (+)-[(14)C]catechin-fed animals is described; a high proportion of residual radioactivity was found in urine that had been exhaustively extracted with diethyl ether.
Abstract: 1. The fate of (+)-[U-(14)C]catechin and (+)-[ring A-(14)C]catechin has been studied in the guinea pig and rat. 2. (+)-[U-(14)C]Catechin was shown to give rise to labelled phenolic acids, labelled phenyl-gamma-valerolactones and (14)CO(2). 3. (+)-[ring A-(14)C]-Catechin did not give rise to labelled phenolic acids, but labelled phenyl-gamma-valerolactones were detected together with a higher proportion of (14)CO(2). 4. Administered [(14)C]delta-(3-hydroxyphenyl)-gamma-valerolactone gave rise to labelled m-hydroxyphenylpropionic acid in the rat whereas administered [(14)C]m-hydroxyphenylpropionic acid gave rise to a compound yielding labelled m-hydroxybenzoic acid on hydrolysis. 5. The distribution of radioactivity in the urine and faeces of (+)-[(14)C]catechin-fed animals is described; a high proportion of residual radioactivity was found in urine that had been exhaustively extracted with diethyl ether.
TL;DR: The distribution of phosphatidylinositol kinase in subcellular fractions from rat brain, kidney, heart, skeletal muscle and testis indicates that the enzyme is most active in fractions likely to contain the plasma membrane of these tissues.
TL;DR: The advantage of the biometrical genetical aproach which is developed lies in its predictive value across generations; an important feature which is not a part of any of the alternative analyses currently in use.
Abstract: THE description and estimation of the components of phenotypic expression have been presented for two or more inbred lines and the F1 crosses between them by Bucio Alanis (1966), Bucio Alanis and Hill (1966) and Perkins and Jinks (1 968a and b), and the approach has been illustrated by the analysis of data from .J'iicotiana rustica grown in different seasons and locations. The most important finding to emerge from these analyses is that the genotypeenvironmental interaction component is often a linear function of the additive environmental effects. The same relationship has been found in other species grown in a variety of environments using different analytical approaches (e.g. Yates and Cochran, 1938; Finlay and Wilkinson, 1963; Eberhart and Russell, 1966; Breese, 1969). The advantage of the biometrical genetical aproach which we have developed, however, lies in its predictive value across generations; an important feature which is not a part of any of the alternative analyses currently in use. This aspect will be illustrated by extending the model and analysis to include the F2 and backcross generations of an initial cross between two inbred lines. In the present paper we will confine our attention to the mean genotype of these segregating generations leaving the variation within the generations for a later paper.
TL;DR: Mechanisms for the overall control of fuel utilization in the locust are discussed and variations in the concentrations of free amino acids in haemolymph are reported.
TL;DR: The data used in the present investigation are derived from observations on all Birmingham live births in the period 1 January 1950 to 1 September 1954 and Verbal reasoning scores from the results of the eleven-plus examinations were matched for 50,172 children.
Abstract: There have been two main approaches to investigation of the relation of birth weight to intelligence. In one, birth weights of children of low intelligence are compared with those of children of average or high intelligence. Where the comparison has been between children in ordinary schools, as in Ascher & Roberts’s study (1949) in primary, grammar and secondary schools, birth weight differences have usually been unimpressive or absent ; but among the subnormal, mean birth weight appears to be reduced and the reduction is present even after exclusion of those whose low intelligence is associated with physical abnormalities (Barker, 1966). The more usual approach has been to measure the intelligence of children of different birth weights. Numbers investigated by this procedure are, as a rule, rather small and the methods of analysis sometimes make it difficult to assess the results. However, the general conclusion which has been reached is that when children with physical abnormalities-such as blindness, deafness and cerebral palsy-are excluded, the intelligence of the remaining children of low birth weight is about normal (McDonald, 1964). In children of very low weights, however, intelligence appears to be reduced (Drillien, 1964). The relation of intelligence to duration of gestation is even less well established, but the contemporary viewpoint is probably summarized in Baird’s conclusion (1959) that ‘there is no clear indication that within wide limits premature expulsion from the uterus does the foetus any serious harm ’. The data used in the present investigation were described in a preceding paper (Record, McKeown & Edwards, 1969). Briefly, they are derived from observations on all (86,630) Birmingham live births in the period 1 January 1950 to 1 September 1954. Verbal reasoning scores from the results of the eleven-plus examinations were matched for 50,172 children and birth weight and duration of gestation (estimated to the nearest week from the first day of the last menstrual period) were available from obstetric records for 41,534 single births.
01 Jan 1969
TL;DR: In this article, the EDTA titration was used for the determination of the metal in organic compounds containing calcium, magnesium, zinc, barium, manganese, or cobalt.
TL;DR: In this paper, a general discussion of the superfluidity of a dense liquid is given, in which it is shown that high rates of shear give difficulty, and an equation is constructed which describes the flow of a continuous incompressible superfluid at zero temperature with a resistance to shear.
TL;DR: In this paper, the compressive deformation of polycrystalline ǫ-zirconium hydride has been investigated within the temperature range 22 to ∼ 400° C and over the composition range ZrH1.71 to Zrh1.92.
Abstract: The compressive deformation of polycrystalline ɛ-zirconium hydride has been investigated within the temperature range 22 to ∼ 400° C and over the composition range ZrH1.71 to ZrH1.92. The observed deformation modes included slip, creation of new lamellae of different orientations to those of the main transformation lamellae, and movement of lamellar boundaries. The results are considered in terms of the contribution of these three processes to the overall deformation behaviour.
TL;DR: It was found in 21 (41%) of 52 patients with untreated adult cœliac disease, 5 (13%) of 38 patients with regional enteritis, and 5 (22%) of 23 patients with ulcerative colitis.
TL;DR: In this paper, some methods of scoring players in a round-robin tournament are proposed, based on a concept of fair allocation of rewards to each player, related to those determined by a previously suggested principle of "consistency".
Abstract: SUMMARY Some methods of scoring players in a round-robin tournament are proposed, based on a concept of fair allocation of rewards to each player. The scores are related to those determined by a previously suggested principle of 'consistency'. The scoring systems lead to the 7rr's of the Bradley-Terry model, and they have desirable ranking properties in the case of a general linear model. Various other properties of the scores are described.