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Notes: Summary Single neurons in the auditory cortex of anesthetized cats were examined quantitatively for their sensitivity to the sound pressure level of characteristic frequency (CF) tone pulses, and to 6 dB, linear modulations in the amplitude of a continuous CF carrier tone. The direction and rate of amplitude modulation (AM), and the carrier level on which it was imposed, were manipulated parametrically. Studied with amplitude modulations, the majority of neurons responded only to intensity increments. The minimum carrier level upon which an amplitude modulation was able to evoke spike discharges was typically comparable to the tone pulse threshold SPL. For many neurons, an “intensity increment response area”, i.e., the domain of AM rate and carrier level conjunctions within which a 6 dB AM was able to evoke discharges, could be delimited. For many neurons, preferred rate of AM drifted from high to low with increases in the carrier level on which the modulation was imposed. The most vigorous responses to AM stimuli often occurred when the carrier levels were associated with the rising slope or the peak of the tone pulse rate intensity function. It may be possible to understand the general form of AM response areas in terms of short-term adaptation, the disposition of excitatory and inhibitory tone pulse response areas, and the spectra of the AM stimuli used.

Notes: Summary In the primary auditory cortex of cats anaesthetized with nitrous oxide, single neurones were examined with respect to their responses to tone bursts and linear modulations of the frequency of an on-going continuous tone. Using FM ramps of 2.0 kHz excursion and varying centre frequency, each of 39 neurones was examined for its preference for the direction of frequency change of a ramp whose centre frequency was varied in and around the neurone's response area. Direction preference was strictly associated with the slopes of the cell's spike count-versus-frequency function over the frequency range covered by the ramp. Preferences for upward- and downward-directed ramps were associated with the low- and high-frequency slopes of the spike count function, respectively. The strength of the cell's direction preference was associated with the relative steepness of the spike count function over the frequency range covered by the ramp. The timing of discharges elicited by the frequency modulations was found to be the sum of the cell's latent period for tone bursts plus the time after ramp onset that the stimulus frequency fell within the neurone's response area. The implications of these data for the processing of narrow and broad frequency-modulated ramps are discussed.

Notes: We have carried out a computational investigation of the ground 1A1 and lowest energy B2 states of the titanium dioxide molecule. The treatment utilized SCF calculations in an extended basis followed by a CI treatment for each geometry. Our ground state geometry agrees well with experiment, while the agreement between the computed vibrational frequency ν1 and the experimental value for a matrix isolated TiO2 is less satisfactory. Population analysis for the ground state indicates less than one excess electron on each oxygen atom. The first excited state has a linear geometry and the singlet and triplet are essentially degenerate.

Notes: Two biotypes of Sorghum halepense (L.) Pers., (Johnson grass) one which overwinters and one which does not overwinter from rhizomes at the northern limit of their North American ranges, were compared for rhizome production, rhizome survival and physiological tolerance to cold. The two biotypes differed in both the amount and depth of rhizome production under field conditions, with the non-overwintering biotype producing very few rhizomes 20 cm below the soil surface. Rhizome survival was clearly related to depth of burial for both biotypes. Survival was much reduced in the top 20 cm of soil and increased at greater depths to nearly 100% survival at depths of 40 to 50 cm. Differences in rhizome survival were apparent between the two biotypes and under the two climatic conditions tested, with greatly reduced survival of the overwintering biotype in the more extreme northern field plot. Similar levels of cold hardiness were observed in both hardened seedlings and rhizomes of the two biotypes. These levels were low and, in general, would not provide major protection against freezing temperatures. La profondeur des rhizomes; facteur critique de la siurvie hivernale de Sorghum halepense (L.) Pers. (Sorgho d'Alep)Deux biotypes de Sorghum halepense (L.) Pers. (Sorgho d'Alep), l'un capable et l'autre incapable d'hiverner à l'état de rhizomes à la limite septentrionale de leurs aires nord-américaines, ont été comparés pour leur production en rhizomes, la survie de ces rhizomes et la tolérance physiologique au froid. Les deux biotypes différaient à la fois par la quantité et le niveau de profondeur de leur production de rhizomes au champ :le biotype incapable d'hiverner produisait très peu de rhizomes à une profondeur de 20 cm. La survie des rhizomes était clairement reliée à la profondeur d'enfouissement pour les deux biotypes. La survie était réduite dans les premiers 20 cm de sol et augmentait avec la profondeur jusqu'à presque 100%à des profondeurs de 40 à 50 cm. Des différences de survie des rhizomes étaient apparentes entre les deux biotypes sous les deux conditions climatiques étudiées, le biotype capable d'hiverner présentant un taux de survie fortement réduit dans la parcelle expérimentale située le plus au Nord. Des niveaux similaires d'endurcissement au froid ont été observés dans des plantules et des rhizomes endurcis des deux biotypes. Ces niveaux étaient bas et en général ne fournissaient pas de protection majeure contre le gel. Tiefenlage der Rhizome: der kritische Faktor fur das Ueberleben von Sorghum halepense (L.) Pers. während des WintersZwei Biotypen von Sorghum halepense (L.) Pers. von der nördlichen Grenze ihres Verbreitungsgebietes in N-Amerika wurden in Bezug auf Rhizomproduktion, Ueberleben ihrer Rhizome und physiologisch bedingte Kälteresistenz miteinander verglichen. Der eine der beiden Biotype überwintert nicht, der andere überwintert, d.h. reproduziert neues Wachstum aus den bestehen-den Rhizomen. Die beiden Typen zeigten unter Feldbedingungen Unterschiede in der Rhizom-bildung, sowohl bezüglich Menge und Tiefenlage der neubildung, wobei der nicht überwinternde Biotype sehr wenig Rhizome tiefer als 20 cm unter der Bodenorberfläche bildet. Das Ueberleben während des Winters war für beide Biotypen eindeutig mit der Tiefenlage der Rhizomasse korreliert. Die Uebelebensrate war in den obersten 20 cm sehr reduziert und nahm mit zunehmen der Tiefe bis zu fast 100% in 40–50 cm Tiefe zu. Es wurden eindeutige Unterschiede in der Ueberlebensrate zwischen den beiden Biotype unter den zwei untersuchten Klimabedingungen festgestellt, wobei ein stark verringertes Ueberle-benspotential des überwinternden Typs unter den extremeren nördlicheren Feldbedingungen beobachtet wurde. Abgehärtete Sämlinge und Rhizome beider Biotypen wiesen einen ähnlichen Grad von Kälteresistenz auf. Diese Resistenz war relativ gering und stellte in der Regel keinen genügenden Schutz gegen Frost dar.

Notes: In his 1950 Marett Lecture, Professor Evans-Pritchard gave an account of important methodological developments which had taken place in social anthropology. I should like to use the occasion to concentrate on some of the deep contemporary divisions in another subject which interested R. R. Marett, namely, the philosophy of religion. I shall do so, however, by reference to some of the methodological issues which concerned Evans-Pritchard.