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Sont presentes de nouveaux resultats experimentaux concernant la propagation de detonations spheriques divergentes sur de grands rayons ( R ⩽ 500 mm). Les mesures ont ete effectuees avec divers melanges gazeux (oxygene-propane-azote, oxygene-acetylene-azote ou helium ou argon, melanges isometriques de methane-oxygene stoechiometrique) tous dans les memes conditions initiales (1 bar, 293°K) et amorces avec le meme apport d'energie par fil explosif. Le parametre de l'etude etait soit la dilution en inerte soit la composition du combustible dans le cas des melanges isometriques. De l'analyse des enregistrements de la frequence Doppler obtenue a l'aide d'un dispositif micro-ondes, la variation de la celerite locale D S ( R ) a ete deduite en fonction de l'abscisse radiale R . Pour les grandes valeurs de R la celerite D S ∞ asymptotiquement atteinte a ete mesuree et la celerite moyenne D deduite du temps de transit entre le centre et la peripherie de la bombe. Une correlation a ete etablie entre le signe et l'amplitude du coefficient δ = (D S∞ − D ) D S∞ et les limites de detonabilite du melange considere. De l'analyse des diagrammes D S ( R ) et la comparaison avec D S ∞ il est apparu que la detonation pouvait etre obtenue immediatement ( D S ( R ) > D S ∞ ) ou bien une zone de predetonation etait observee ( D S ( R ) D S ∞ ).

Resume Un melange explosif etant considere comme la reunion de plusieurs substances explosives, des relations simples sont etablies donnant les principales caracteristiques du melange global en fonction de deux seulement de chacune des substances le composant. Le developpement theorique est base sur l'additivite des enthalpies, hypothese qui se trouve verifiee par ses consequences. Des valeurs numeriques calculees sont comparees aux valeurs mesurees pour quelques cas de melanges explosifs solides et liquides. Une excellente coincidence est alors constatee.

Le détour n'est qu'apparent entre le thème des conditions de travail et celui des structures d'organisation de l'entreprise, si l'on admet avec les auteurs la commune référence de Max Weber et de Taylor à la théorie rationaliste qui sous-tend la recherche du «one best way». N'est-ce pas d'ailleurs cette même théorie qui fonde l'universalité des modèles d'organisation des études dont M. Brossard et M. Maurice montrent les limites, proposant de situer l'entreprise dans la société, pour mieux saisir les effets de chaque société sur son organisation ?, Brossard Michel, Maurice Marc. Existe-t-il un modèle universel des structures d'organisation ?. In: Sociologie du travail, 16ᵉ année n°4, Octobre-décembre 1974. Conditions de travail. Le taylorisme en question, sous la direction de Marc Maurice. pp. 402-426.

The addition of 0.1 M KCl to, or the omission of CaCl2from, incubation media in which rat brain cortex slices are respiring, stimulates the incorporation of inorganic P32into phospholipids. It also stimulates the labelling of 7-minute hydrolyzable nucleotide phosphates, but decreases their levels. The stimulation of P32incorporation into total phospholipid takes place primarily into phosphatidic acid and phosphoinositide but not into phosphatidyl choline and phosphatidyl ethanolamine. The addition of succinate and γ-aminobutyrate to brain cortex slices, metabolizing glucose, markedly inhibits the labelling of phospholipids although the respiration of slices is not diminished. The potassium stimulation of phospholipid labelling only occurs if sodium ions are present in the incubation medium. The lesser stimulation due to absence of calcium ions seems, however, to be independent of the presence of sodium ions. Acetylcholine stimulation of P32incorporation into phospholipids is dependent on the presence of sodium ions. Such stimulations are suppressed by concentrations of malonate, iodoacetate, fluoride, and ethanol that have little effect on the unstimulated incorporation of P32. Atropine and hyoscine inhibit acetylcholine stimulation but not cationic stimulation of P32incorporation. It is suggested that the effect of acetylcholine on P32incorporation is mediated by cationic changes at the nerve cell membrane.

Recent theoretical considerations have led to the conclusion that a cylindrical expanding detonation wave cannot simultaneously be a steady detonation wave and satisfy the Chapman-Jouguet condition. However, despite the development of measurement techniques, the results of experimental investigations have not permitted definitive conclusions. The purpose of this paper is to contribute to the solution of these problems by analyzing the results of our observations on cylindrical expanding detonation waves in C 3 H 8 + X O 2 + Z N 2 mixtures at atmospheric pressure and room temperature, contained in expanding sectors. Detonation was produced by an exploding wire (34 joules/cm) located exactly in the angle of the sector, and the wave velocity was measured by means of ionization probes. The structure of the wave was observed by means of streak-schlieren and soot techniques. By comparing our experimental results with corresponding results for plane detonations propagating in tubes, it was possible to specify: o (i) The limits of detonability as a function of the thickness of the sector and the composition of the propane-oxygen-nitrogen mixtures; (ii) The value of the velocity of propagation which did not change notably with the distance traveled but which could be higher or lower than the Chapman-Jouguet velocity; (iii) A D ∞ value which can be obtained by extrapolating the observed velocities D (1/ h ) to 1/ h =0. (iv) The instability phenomena characterized at very high frequencies by striae in the structure of the detonation front.

In a traditional Institution, 48 infants, of both sexes, whose chronological age ranged from 2 to 3 months, were equally divided into four groups (3 experimental and 1 control group) and for a period of two months were submitted, daily, to three main types of stimulation: (1) perceptual, (2) social, and (3) perceptual ‐‐ social. A thought provoking conclusion emerges from the preliminary results: 2‐3‐months‐old institutionalized infants, who receive varied perceptual stimulation during a 10‐week period, present a developmental profile almost identical to the developmental profile of infants of the same age. I.Q.s and environment, who received, during the same length of time, a social stimulation through the agency of one person.

The selective influence of school as far as working class children are concerned, has been brought forward by several works on sociology and psychology of education. The linguistic level and the attitudes toward language would, among others, be a determining factor of school success or failure. So Basil Bernstein tried to point out the language characteristics of the working class children and of the middle class children. But not a sociology of « differences » stiffen the pattern of those differences. Besides are these differences as deep as they seem ? Denis Lawton in « Social class, language and education » began to explore all these questions which are both theorical practical since they have a direct incidence on education practice. Through this experimental researches Lawton shows the necessity of carrying on the analysis of the level of psychology ans pedagogy. He points out that the differences between the linguistic performances of children coming from different socio cultural surroungdings are not so much a matter of having different codes, as an ability to « switch r> from a restricted code to an elaborate code. When they have to face a linguistic task requiring the use of a complex language the working class children produce utterances which are not very different from those produced by the middle class children. It is therefore necessary to give special care to the teaching situation requiring or not the use of more or less elaborate utterances on behalf of the children. This approach, both from a sociological and psychological point of view would allow us to determine scientifically what the conditions of truly democratic teaching are., De nombreux travaux de sociologie et psychologie de l'éducation ont mis en lumière le rôle sélectif joué par l'école à l'égard des enfants des classes populaires. Le niveau linguistique, les attitudes à l'égard du langage joueraient, entre autres, un rôle déterminant dans la réussite ou l'échec scolaire. Ainsi Basil Bernstein s'est-il efforcé de dégager les caractéristiques du langage des enfants issus des « working class » ainsi que celles des enfants issus des ce middle class ». Mais une sociologie des ce différences » ne risque-t-elle pas de figer ces mêmes différences ? Par ailleurs est-on sûr que ces différences soient si profondes ? Toutes ces questions à la fois théoriques et pratiques (puisqu'elles ont une incidence directe sur la pratique éducative) commencent à être explorées par Denis Lawton dans son ouvrage ce Social class, language and education ». Par ses recherches expérimentales D. Lawton montre la nécessité de poursuivre l'analyse sur un plan psychologique et pédagogique. Il montrera que ce qui différencie les performances linguistiques des enfants, issus de deux milieux socio-culturels différents, n'est pas tant une différence de « code », qu'une plus ou moins grande aisance à passer d'un « code restreint » à un. a code élaboré ». Face à une tâche linguistique nécessitant un langage complexe, les enfants des working-class produisent des messages qui les rapprochent des enfants des middle-class. Aussi faut-il porter une attention toute particulière à la situation pédagogique qui nécessitera, ou non, de la part de l'enfant le recours à des formes de messages plus ou moins élaborées. L'approche à la fois sociologique et psychologique permet de déterminer avec rigueur les conditions d'une pédagogie effectivement démocratique., Brossard Michel. Langage, opérativité, milieu culturel.. In: Enfance, tome 25, n°5, 1972. Recherches sur l'acquisition du langage chez l'enfant. pp. 455-468.

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The Canadian Shield is an area of Pre‐Cambrian rocks some 2,000,000 square miles in extent, which produces a half‐billion dollars worth of minerals per year. The geophysical prospecting methods of most use here are magnetic and electrical. Geophysical methods, after recovering from an earlier period of disfavor, are now beginning to be properly appreciated by the local mining industry. Several examples of important recent geophysical discoveries are presented. Future expansion in this field appears inevitable.

We describe the use of semiconductor telescopes to detect, to identify and to measure the energy of the recoil nucleus in proton-nucleus coherent interactions at 600 MeV. Preliminary results are obtained using 3 He and 4 He gaseous targets with a pressure of one atmosphere.

The blood of two groups of five neonates was exchanged to manage a hemolysis due to ABO incompatibility. Exchange transfusions were performed with ACD or CPD blood stored for less than 48 h. Blood oxygen affinity, hemoglobin, and 2,3-diphosphoglycerate concentrations, plasma and erythrolysate pH were measured on blood samples before and several times during the 24 h following the exchange. Infants transfused with CPD blood increased their P50 and 2,3-DPG concentration more rapidly than the group receiving ACD blood. Estimates of oxygen unloading capacities have been calculated, taking into account variations in hemoglobin concentration, P50, and pH. Assuming a constant cardiac output, transfusion with CPD blood might be more valuable than with ACD blood to insure oxygen transport, especially in infants with respiratory or cardiac impairments.

The effects of growth hormone and hydrocortisone on the synthesis of rat liver RNA have been studied. Administration of growth hormone stimulated the incorporation of 14C-orotic acid into 45 S preribosomal nucleolar RNA, and had no effect on the 6–50 S polydisperse nuclear RNA of extra-nucleolar origin. On the other hand, hydrocortisone stimulated the synthesis of all types of nuclear RNA, but mainly that of the 18 S class of 6–50 S polydisperse nuclear RNA.

Vibratory phenomena and instability of self- sustained detonations in gases - propagation velocity measurements

The word “Confederation” is often used in a restrictive sense to refer merely to the “British North America Act”; in this restricted sense, it refers to the constitution of Canada. In its broader sense, it should refer to the union of the entire population of Canada, grouped together, on the one hand into provinces, and on the other hand into Canadians of French and English descent, for the attainment, the development, and the protection of interests common to all, while safeguarding for each group, whether province or race, the rights and traditions peculiar to it. These two understandings of Confederation are indispensable for a better comprehension of the attitude of French Canada towards it.Two lines of thought as to the understandings, agreements, pacts, or contracts—call them what you like—which were satisfactorily or unsatisfactorily formulated by the British North America Act must be noted. While for the majority of Anglo-Canadian constitutional authors the pacts of 1864, 1865, and 1866 were primarily made between provinces, one of which happened to be populated for the most part by Canadians of French descent, for French-Canadian constitutional writers these pacts were at one and the same time agreements between the four original provinces on the one hand and between the two great races on the other hand. The fact that Sir George Etienne Cartier and other French Fathers of Confederation did not, at the time, foresee that at some future date the provinces of Canada other than Quebec would also be populated by an important number of French Canadians, and that they consequently directed all their efforts for the safeguarding of the rights of French Canadians to securing for the province of Quebec the largest possible amount of independence, does not, in our opinion, change the above views on the matter.

Decouvert il y a plus de 50 ans, dans des huiles de foies de squaloides, le squalene C30 H50 a ete ensuite identifie et dose dans plusieurs huiles d'origine vegetale.

Metric axioms have been given in [3] for space euclidean geometry. If we replace the "similarity axiom" by the "congruence axiom", where congruence is defined to be a similarity of ratio one, the resulting structure is absolute geometry. In order to show this we choose a suitable definition for absolute geometry. The P a s c h system of axioms, given in an improved formulation by H. S. M. Coxeter in [4], is particularly suitable; the primitive notions are points, betweenness relation, and congruence relation. We can verify that every axiom for the absolute geometry in [4] in a theorem in [3] where the similarity axiom has been replaced by the congruence axiom. The only case for which it is not obvious is axiom 15.15 in [4] which says that if ABC and A' B' C' are two triangles with BC ≡ B'C' CA ≡ C'A1, AB ≡ A ' B ', while D and D' are two further points such that [B, C, D] and [B', C' D'] and BD ≡ B' D', then AD ≡ A' D'. In that case we first prove that if two triangles ABC and A'B C are such that AB/A'B' ≡ BC/B'C' ≡ CA/C'A' ≡ 1 then they are congruent; a proof of this, independent of the similarity axiom, can be found in [2]. The proof of 15. 15 in [4] is then obvious. As every axiom in the weakened structure of [3] is a theorem of absolute geometry we have a definition for this geometry.