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In this paper two effective algorithms are given for optimizing power systems schedules. These algorithms are based on the simplex method. Rapid convergence of the iterative processes, on which these algorithms are based, and a relatively brief calculation time at each iterative step lead to a high efficiency of the procedure for optimizing the schedules.

Brain material from a patient with Creutzfeldt-Jakob disease was inoculated intracerebrally into four squirrel monkeys. Subsequently three out of the four inoculated monkeys developed clinical signs and a syndrome similar to the human disease. The incubation period from inoculation until the appearance of first signs varied from 20 to 23 months. Histological examination of the brains of the above monkeys revealed severe spongy degeneration and astrogliosis, lesions that resembled those seen in the brain of the patient. The findings not only confirm the fact that Creutzfeldt-Jakob disease is transmissible, but also draw attention to the usefulness of the squirrel monkey, a small and easily handled New World monkey, as a laboratory animal for the transmission of human subacute spongiform encephalopathies.

1. The Golgi material of the male germ-cells of the domestic fowl is in the form of a localized body, composed of rods and granules which lie on the surface of the archoplasm. 2. During the maturation divisions the localized Golgi material breaks down and forms a number of granules and rods which become dispersed at the beginning of the metaphase. After each division the scattered Golgi elements reassemble in the daughter cells and become once more attached to the archoplasm. 3. After the formation of the acrosome the Golgi material migrates to the residual cytoplasm and, as the Golgi remnant, is eliminated. 4. Accessory bodies are present in the cytoplasm of the spermatocytes from both silver and chrom-osmium preparations; in the spermatids only argentophil bodies are identified. One argentophil accessory body ‘Golgi X’ is included in the neck region of the spermatozoon. 5. The acrosome is formed from the proacrosome; the latter originates within the archoplasmic vacuole inside the Golgi material of the spermatid. The acrosome occupies the anterior tip of the head of the spermatozoon, and is conical in shape. 6. The nuclear ring is present in the early stages of the metamorphosis of the spermatid; with the elongation of the nucleus it disappears. 7. The mitochondria are described during all the stages of spermatogenesis; their ultimate fate is the formation of the mitochondrial sheath of the middlepiece. This sheath often appears in the form of a spiral structure. 8. During the transformation of the nucleus a coiled stage is constant; this is due to the continuous elongation of the nucleus and lack of response from the cytoplasm. The head of the spermatozoon is an elongate worm-like structure. 9. Two centrioles are present in the spermatids of the domestic fowl. The axial filament originates from the two centrioles. The proximal centriole is attached to the posterior end of the head of the spermatozoon, while the distal centriole assumes the shape of a ring and marks the distal limit of the middlepiece. 10. A clear zone surrounds the posterior part of the nucleus of the late spermatid; this zone possibly takes part in the formation of the middle-piece.

1. The Golgi material of the pyramidal cells of the cerebral cortex, the Purkinje cells of the cerebellum, and the multipolar cells of the medulla oblongata and ventral horns of the spinal cord of the sheep is present as filaments and as irregularly shaped bodies. In some of the cells, particularly in the lamb (Sheep V), the Golgi material has the appearance of a network. As it is frequently present as separate bodies it is suggested that it may always consist of discrete Golgi elements which are sometimes situated in close proximity or in contact with one another. Filamentous Golgi elements are present in the basal part of the cell processes. 2. An examination of neurones from the corresponding regions of the central nervous system of sheep infected experimentally with louping-ill showed that the Golgi material undergoes changes consequent upon the invasion of the cells by the virus. The Golgi material undergoes hypertrophy, and at the same time there is a reduction in the number of filamentous Golgi elements and a reduction in the amount of Golgi substance present in the cell processes. These changes are followed by fragmentation. All the neurones of a particular region are not affected equally at the same time. The Golgi material of the Purkinje cells tends to form groups in the cytoplasm prior to fragmentation. In the multipolar cells of the medulla oblongata the hypertrophy of the Golgi material is not as great as in the other regions of the central nervous system. The Golgi material of the motor nerve-cells of the ventral horns of the spinal cord undergoes considerable hypertrophy which is followed by a grouping of the Golgi elements and fragmentation.

The present paper gives an account of the behaviour of the Golgi material, mitochondria, and nucleolar extrusions during the oogenesis of dog, cat, and rabbit. So far as the writer is aware there is no previous detailed work on the cytoplasmic components of the female germ-cells of the animals investigated.R. Vander Stricht (1911) dealt with the oogenesis of the cat; O. Vander Stricht (1923) has made a comparative study of oogenesis of mammals, including the dog and the cat; P. del Rio Hortega (1913) described the behaviour of the Golgi material, and H. von Winiwarter (1900) studied the nuclear changes during oogenesis of the rabbit; H. von Winiwarter and G. Sainmont (1909) dealt with nuclear metamorphosis during the oogenesis of the cat; finally J. Nihoul (1926), in his paper on the rabbit, described the Golgi material during oogenesis. All the papers quoted, apart from those which deal with the nuclear changes, are either incomplete surveys, or the methods used are insufficiently delicate to reveal changes shown by modern techniques.

Some problems of regime control of thermal electric powers-station by use of computers are discussed. The algorithm to calculate the energetic characteristics of power units and the modified algorithm of dynamic programming of load dispatching between electric station power units is give.

We consider the important part played by plasma wave absorption at the higher harmonics of the electron gyrofrequency (under conditions of the so-called double plasma resonance) in the solar corona. An explanation is proposed for the fine structure of Type III bursts on the basis of this effect.

In a controlled experiment in which all the mice inoculated with scrapie were white and those uninoculated were black, four cases of contact infection, proved by histopathological examination, occurred after a period of 15 to 16 months of cohabitation.

An attempt has been made to correlate chemical changes with the degree and extent of histological damage in mouse brains infected with the “Suffolk strain” of scrapie. A scheme is described for the combined grading of degree of brain damage and distribution of lesions based on neuronal vacuolation and spongy degeneration. Considerable variation was found in the extent to which the mice were affected with scrapie. There was good correlation between change in body weight and histological grading and also a progressive decrease in brain weight with increase in extent of lesions. A slight decrease in mean density of brain tissue was observed. Total dry matter and protein concentrations remained constant. The sodium concentration remained constant, but there was 5 per cent. decrease in potassium concentration. A rise in acid proteinase activity appeared at the same time as minimal lesions, but reached a maximum before widespread lesions were present. There were no gross changes in the concentration of total free amino-acids. Since the total dry matter and protein concentrations alter very little, excess products of protein hydrolysis arising from increased acid proteinase activity must be removed rapidly from the brain. It is possible that the release of waste products may occur in sudden localised outbursts.

Although sex reversal is fairly common in invertebrates, the presence of male characteristics with a female karyotype in mammals merits a detailed examination. Four goats of the Toggenburg strain belonging to the Department of Genetics of the Faculdade de Ciencias Medicas e Biologicas of Botucatu, Brasil, with a small vagina, an enlarged penis, a variable degree of labial fusion and a common opening of the urethra and vagina, were found to have a female karyotype. This was established from the chromosomal pattern of cultured leucocytes and sex chromatin studies of brain tissue cells. The same goats were reported to have

Oogenesis 1. The Golgi material of the oogonium and the early primary oocyte consists of spherical and rod-shaped bodies situated at one side of the nucleus. In older oocytes it is present as rods and granules distributed through the cell. 2. Granular mitochondria surround the nucleus of the oogonium and the early primary oocyte. In older oocytes they are scattered in groups through the cytoplasm. Later, they are arranged in a broad peripheral zone. In oocytes of Graafian follicles the majority of the mitochondria are situated in the central cytoplasm. 3. Small fat globules are present in young oocytes. In older oocytes the globules increase in size and number. There is a reduction in the size of the Golgi elements at the time when there is a marked increase in the amount of fat; this suggests that the Golgi material plays a part in the formation of the globules. Nucleolar material appears to be passed into the cytoplasm; it may contribute to the formation of nutritive material. 4. The position of the Golgi material of the follicle-cells suggests that the cells at first form a secretion which is passed into the oocyte, and later a secretion which enters the follicular cavity. Secretory granules are visible in many of the cells of late follicles. The position of the mitochondria appears to be correlated with the functional polarity of the cell. Spermatogenesi 1. The Golgi material of the spermatogonium, resting spermatocyte, and early spermatid consists of rods and granules situated at one side of the nucleus. The Golgi elements separate into two groups during nuclear division. Argentophilic and osmiophilic granules present at the posterior pole of the nucleus of the late spermatid probably originate from the Golgi material. The Golgi remnant is eliminated with the residual cytoplasm. 2. Accessory bodies are present in primary spermatocytes and in spermatids. An accessory body is present in the neck region of the spermatozoon. 3. The mitochondria are granular; their behaviour during spermatogenesis is described. 4. The formation of the acrosome and the nuclear-ring is briefly described. 5. The distal centriole passes undivided to the posterior end of the middlepiece. The manchette marks out the cytoplasm which is included in the middle-piece. 6. The protoplasmic bead, present at the anterior end of the middle-piece, is formed while the spermatozoon is within the testis.

Identification of unconjugated dehydroepiandrosterone (D) and 16α-hydroxydehydroepiandrosterone (16α-OH-D) isolated from 500 ml of cord plasma obtained from mixed arterial and venous cord blood collected after vaginal delivery at term is presented. The identification is based upon in vitro placental conversion of D and 16α-OH-D to 17β-estradiol and estriol respectively, further on formation of D acetate and 16α-OH-D diacetate and their thiosemicarbazones, and finally on reduction of the acetates and repeat acetylation. All acetates were doubly labelled and chromatographed to constant 3 H/ 14 C ratios. Constant ratios were also obtained in recrystallizations of D acetate and 16α-OH-D diacetate after reversed isotope dilution.

When a mixture of dry ice and pentane is subjected to high vacuum for one hour the temperature of the mixture is reduced to -125° C. The low temperature of the dry ice/pentane mixture persists for about ½ h and rises only very slowly thereafter. The chilled dry ice mixture when used for the initial cooling of tissues produces good cytological preservation.