3,052 research outputs found
Contrasting activity profile of two distributed cortical networks as a function of attentional demands
No full textThe original publication is available at http://www.jneurosci.orgThis work was supported by R01 grant MH-073610 from the National Institutes of Health to Denis Paré
Development of the inflorescence and flower of Philodendron fragrantissimum (Araceae): A qualitative and quantitative study
No full textThe early stages of inflorescence development in Philodendron fragrantissimum (Hook.) G. Don are examined using scanning electron microscopy. Pistillate flowers are initiated on the lower portion of the inflorescence and staminate flowers are initiated on the distal portion. Male flowers have 6-8 stamens (sometimes 5) and female flowers have a multilocular ovary consisting of 6-10 locules. A transition zone consisting of sterile male flowers and bisexual flowers with fused or free carpels and staminodes is also present. This zone is located between the male- and female- flower zones. Generally, the portion of the bisexual flower adjacent to the male zone forms staminodes and the portion bordering the female zone develops an incomplete gynoecium with few carpels. The different floral organs of the bisexual flowers are all inserted in the same whorl. Pistillate and staminate flowers are inserted on the same contact parastichies along the inflorescence; there is no spatial discontinuity between the female zone, the bisexual zone, and the male zone. The presence of bisexual flowers is believed to correspond to a morphogenetic gradient at the level of the inflorescence as a whole. A quantitative analysis of a series of parameters (i.e., length and width of flower types and inflorescence zones) indicates that each zone of the inflorescence has its own particular nature as far as rhythm of growth and geometry are concerned. There appears to be evidence for some form of partitioning in the global development of the inflorescence. The growth of a zone seems to be more variable in size and geometry than that of individual flowers. During later stages of development, the size of the flowers of the intermediate zone, especially the sterile male flowers, increases considerably, until it exceeds that of both male and female flowers.Source type: Electronic(1
Developmental morphology of normal and atypical flowers of Philodendron insigne (Araceae): A new case of homeosis
No full textThe early stages of development of the inflorescence of Philodendron insigne were examined using scanning electron microscopy. Pistillate flowers are initiated on the lower portion of the inflorescence and staminate flowers are initiated on the distal portion. The male flowers have three to five stamens. The female flowers have a multilocular ovary consisting of three to five locules. A transition zone consisting of sterile male flowers and atypical bisexual flowers with fused or free carpels and staminodes is located between the male and female floral zones. Generally, the portion of the bisexual flower facing the male zone forms stamens, and the portion facing the female zone develops one or two carpels. In P. insigne, the incomplete separation of staminodes from the gynoecial portion of the whorl shows that the staminodes and carpels belong to the same whorl. The atypical bisexual flowers of P. insigne are believed to be a case of homeosis where carpels have been replaced by sterile stamens on the same whorl. However, there is no regularity in the number of organs involved in the homeotic transformation taking place in atypical bisexual flowers. The presence of atypical bisexual flowers may correspond to a morphogenetic gradient at the level of the inflorescence as a whole.Source type: Electronic(1)http://proquest.umi.com/pqdweb?did=279053581&Fmt=7&clientId=65345&RQT=309&VName=PQ
Study of homeosis in the flower of Philodendron (Araceae): A qualitative and quantitative approach.
No full textThis study deals specifically with floral organogenesis and the development of the inflorescence of Philodendron squamiferum and P. pedatum. Pistillate flowers are initiated on the lower portion of the inflorescence and staminate flowers are initiated on the distal portion. An intermediate zone consisting of sterile male flowers and atypical bisexual flowers with fused or free carpels and staminodes is also present. This zone is located between the sterile male and female floral zones. In general, the portion of bisexual flowers facing the male zone forms staminodes, and the portion facing the female zone develops an incomplete gynoecium with few carpels. The incomplete separation of some staminodes from the gynoecial portion of the whorl shows that they belong to the same whorl as the carpels. There are two levels of aberrant floral structures in Philodendron. The first one is represented by the presence of atypical bisexual flowers, which are intermediates between typical female flowers and typical sterile male flowers. The second one is the presence of intermediate structures between typical carpels and typical staminodes on a single atypical bisexual flower. The atypical bisexual flowers of P. squamiferum and P. pedatum are believed to be a case of homeosis where carpels have been replaced by sterile stamens on the same whorl. A quantitative analysis indicates that in both species, on average, one staminode replaces one carpel.PT: J; UT: BIOSIS:PREV200300025461ME: printSource type: Print(0
Development of the flower and inflorescence of Arum italicum (Araceae)
No full textThe spadix of Arum italicum Miller consists of two main parts: a clavate sterile portion (appendix) and a cylindroid fertile portion. In the fertile portion with both male and female zones, there are two zones of sterile flowers (bristles). The basal portion of bristles is surrounded by a verrucose structure consisting of a mass of tissular excrescences. During early stages of development, there is no free space between the different zones of the inflorescence. The elongation of the inflorescence axis is what eventually separates the different zones from each other. There are no atypical flowers that are morphologically intermediate between male and female flowers as is the case in other genera of Aroideae (e.g., Cercestis, Philodendron, Schismatoglottis). The structure of the bristles in the inflorescences of Arum does not correspond to any type of atypical flower (unisexual or bisexual) that has been analysed previously in the Araceae. From a developmental point of view, it is not possible to determine if the bristles correspond to aborted or modified female or male flowers. In the early stages of development, the stamens, staminodes, and appendix are covered by globular masses of extracellular calcium oxalate crystals. [PUBLICATION ABSTRACT] Key words: development, unisexual flowers, gradient, calcium oxalate crystals.Source type: Electronic(1
Is Tolerance Political? An Interview with Denis Lacorne
No full textcontribution à un site webDenis Lacorne is the author of "The Limits of Tolerance. Enlightenment Values and Religious Fanaticism" (Columbia University Press, 2019), the English translation of "Les limites de la tolérance" (Gallimard, awarded the Prix Montyon by the Académie Française). In his book, which is intellectually very inspiring because of the many questions it addresses and raises, Denis Lacorne traces the emergence of the notion of tolerance from its early thinkers to the Age of Enlightenment and finally questions the notion and its various understandings through more recent events in France and the United States. What is tolerance? Is tolerance political? Interview by Miriam Périer, CER
Timing of impulses from the central amygdala and bed nucleus of the stria terminalis to the brainstem
No full textThe amygdala and bed nucleus of the stria terminalis (BNST) are thought to subserve distinct functions with the former mediating rapid fear responses to discrete sensory cues and the latter longer “anxiety-like” states in response to diffuse environmental contingencies. Yet, these structures are reciprocally connected and their projection sites overlap extensively. To shed light on the significance of BNST-amygdala connections, we compared the antidromic response latencies of BNST and central amygdala (CE) neurons to brainstem stimulation. Whereas the frequency distribution of latencies was unimodal in BNST neurons (~10 ms mode), that of CE neurons was bimodal (~10 and ~30 ms modes). However, after stria terminalis (ST) lesions, only short-latency antidromic responses were observed, suggesting that CE axons with long conduction times course through the ST. Compared to the direct route, the ST greatly lengthens the path of CE axons to the brainstem, an apparently disadvantageous arrangement. Since BNST and CE share major excitatory basolateral amygdala (BL) inputs, lengthening the path of CE axons might allow synchronization of BNST and CE impulses to brainstem when activated by BL. To test this, we applied electrical BL stimuli and compared orthodromic response latencies in CE and BNST neurons. The latency difference between CE and BNST neurons to BL stimuli approximated that seen between the antidromic responses of BNST cells and CE neurons with long-conduction times. These results point to a hitherto unsuspected level of temporal coordination between the inputs and outputs of CE and BNST neurons, supporting the idea of shared functions.The original publication is available at: http://jn.physiology.org/cgi/content/full/100/6/342
Rehab Depot de la Plaine Saint-Denis
No full textRedesign for workshop Atelier Revision Intermediaire at the Depot de la Plaine Saint-Denis with a rehabilitation center as new functionRMITArchitecture and The Built Environmen
Phyllotaxis of the palm Euterpe oleracea Mart. at the level of the shoot apical meristem
No full textPrevious studies on palm phyllotaxis deal mainly with the mature trunk. The goals of this study are (i) to determine the relationship between the number of parastichies, the divergence angle, and the plastochrone ratio at the level of the shoot apical meristem; (ii) to examine whether there are fluctuations in the divergence angle; (iii) to interpret the significance of phyllotactic parameters with respect to the mode of growth of the apex. The tubular base of the leaf primordium is more or less asymmetrical, and completely surrounds the shoot apical meristem. The phyllotactic system corresponds to a (2, 3) conspicuous parastichy pair. The mean divergence angle per apex varies between 126.9 degrees +/- 9.3 degrees (mean +/- SD) and 135.degrees +/- 8.0 degrees. Divergence angles for all apices fluctuate within a range of 115.89 degrees to 157.33 degrees. The mean plastochrone ratios between apices varies from 1.35 degrees +/- 0.18 degrees to 1.58 +/- 0.12. The plastochrone ratio at each plastochrone for all apices ranges from 1.09 to 2.00. There is no correlation between the angle of divergence and the plastochrone ratio. There is a fluctuation in the value of the divergence angle that falls within the range predicted by the fundamental theorem of phyllotaxis. The high value of the ratio of the diameter of leaf primordia over the diameter of the apex, and the long plastochrone might explain the lack of correlation between certain phyllotactic parameters.PT: J; UT: BIOSIS:PREV201000395117Source type: Electronic(1
Severini e Denis
No full textL'A. prende in esame i controversi rapporti tra i due artisti, nel primo decennio del secolo e, più tardi, nella produzione di carattere religioso. Severini risulta influenzato da Denis più di quanto sostenga negli scritti teorici. The Author examines the controversial relationships between the two artists, in the first decade of the century and later on, in their religious production. Severini appears influenced by Denis more than he declares in his theoretic writings
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