932 resultados para Round-table discussions


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The article retraces the career of the famous hypnotist Onofroff and particularly his visit to Buenos Aires, where his activity, in 1895, provoked many discussions and some public embarrassment. In this context Darío, using a pseudonym, published his crónica “La esfinge”. We reproduce “La esfinge”, transcribing the original text of La Nación, with annotations identifying the literary and theosophical sources Darío used when he wrote it.

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This study investigated two hypotheses regarding the mapping of perception to action during imitation. The first hypothesis predicted that as children’s cognitive capacities increase the tendency to map one goal and disregard others during imitation should decrease. This hypothesis was tested by comparing the performances of 168 4- to 7-year-olds in a gestural imitation task developed by Bekkering, Wohlschläger, and Gattis. The second hypothesis predicted that reducing the mapping between perception and action should reduce the demands on the cognitive resources of the child. This hypothesis was tested by creating a condition in which perception and action overlapped by sharing objects between experimenter and child. In three experimental conditions, an adult modelled four gestures, directed at either: 1) one of two sets of round stickers (proprietary objects); 2) the same location on the table, without any sticker (no objects); or 3) one set of round stickers, which were shared with the child (shared objects). The results confirmed both hypotheses. Four- and five-year-olds imitated less accurately when imitation involved mapping of both objects and movements (proprietary and shared objects) than when imitation involved mapping movements only (no objects). Seven-year-olds imitated accurately in all three conditions, demonstrating that increased cognitive capacity allowed them to map multiple goals from perception to action. Most importantly, reducing the mapping between perception and action in the shared objects condition facilitated imitation, specifically for the transitional group, 6-year-olds. We conclude that mapping between perception and action is not direct, but resembles mapping relations in analogical reasoning: cognitive processes mediate mapping from perception to action.

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Tree-ring analysis of subfossil Pinus sylvestris L., from nine new peatland sites located beyond the species’ current northern limit in Scotland, established a regional chronology called WRATH-9. The chronology has been provisionally dated against Irish pine chronologies and provides the first annual resolution picture of Scots pine expansion from c. 3200 bc and subsequent demise from c. 3000 bc. Pine germination and growth is suggested to be associated with a widespread fall in bog water-tables that indicates a regional climatic control. Bog pines progressively declined in number, rather than died out in a single event, reflecting their growth in a marginal habitat, close to a critical ecological threshold. The use of tree-ring sequences from in situ bog pine macrofossils provides a higher resolution insight into past conditions than possible with existing radiocarbon and pollen-based chronologies.

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The university course timetabling problem involves assigning a given number of events into a limited number of timeslots and rooms under a given set of constraints; the objective is to satisfy the hard constraints (essential requirements) and minimize the violation of soft constraints (desirable requirements). In this study we employed a Dual-sequence Simulated Annealing (DSA) algorithm as an improvement algorithm. The Round Robin (RR) algorithm is used to control the selection of neighbourhood structures within DSA. The performance of our approach is tested over eleven benchmark datasets. Experimental results show that our approach is able to generate competitive results when compared with other state-of-the-art techniques.

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Desmoplastic small round cell tumor is a rare malignant neoplasm mostly occurring in the vicinity of or within the peritoneal cavity, and is uncommon in the head and neck region. Tumor location within a major salivary gland is exceptional. We report a case of a 41-year-old Chinese man with a history of diabetes mellitus and end-stage renal failure on peritoneal dialysis with a desmoplastic small round cell tumor occurring in the left submandibular gland. Fine-needle aspiration cytology showed variably cohesive clusters of small cells with hyperchromatic nuclei and fine granular chromatin. On histology the neoplasm displayed classic features of a desmoplastic small round cell tumor with angulated nests of small round blue cells in a fibromyxoid/desmoplastic stroma. Neoplastic cells were immunoreactive for cytokeratins (AE1/3), desmin (paranuclear dot-like), WT-1 (nuclear), epithelial membrane antigen, and CD56. EWS gene translocation and EWS-WT1 gene fusion were detected by fluorescence in situ hybridization and reverse transcriptase polymerase chain reaction, respectively. The case presented is the sixth case of and the oldest reported patient with a desmoplastic small round cell tumor occurring in a major salivary gland to date. Desmoplastic small round cell tumor should be considered in the differential diagnosis of a salivary gland neoplasm with a basaloid or small cell pattern on fine-needle aspiration cytology.

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Desmoplastic small round cell tumor (DSRCT) is a rare undifferentiated neoplasm. The prognosis is poor, even if therapy is instituted promptly. and thus it is important to differentiate it from other histologically and cytologically similar-looking malignancies of the young adult. We present a case of DSRCT in a 17-yr-old male with disseminated peritoneal disease and peritoneal effusion. The cytology sample showed a malignant small round cell tumor, the classical cytological features of DSRCT, and immunohistochemistry performed in the prepared cell block exhibited an antibody expression profile in keeping with DSRCT. Further material front the effusion was prepared for RNA extraction, following which a reverse-transcriptase polymerase chain reaction (RTPCR) and sequencing of the t(l l;22)(p13;q11 or q12) were carried out. The result showed the presence of the reciprocal translocation and thus confirmed the diagnosis of DSRCT. This case shows how molecular techniques (including sequencing) call be applied to cytology in clarifying and confirming certain difficult diagnosis of undifferentiated neoplasms, DSRCT in this particular case. Diagn. Cytopathol. 2003;29:341-343. (C) 2003 Wiley-Liss. Inc.

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In this paper, a model is presented that describes the pressure drop of gas-liquid Taylor flow in round capillaries with a channel diameter typically less than 1 mm. The analysis of Bretherton (J Fluid Mech 10:166-188, 1961) for the pressure drop over a single gas bubble for vanishing liquid film thickness is extended to include a non-negligible liquid film thickness using the analysis of Aussillous and Qu,r, (Phys Fluids 12(10):2367-2371, 2000). This result is combined with the Hagen-Poiseuille equation for liquid flow using a mass balance-based Taylor flow model previously developed by the authors (Warnier et al. in Chem Eng J 135S:S153-S158, 2007). The model presented in this paper includes the effect of the liquid slug length on the pressure drop similar to the model of Kreutzer et al. (AIChE J 51(9):2428-2440, 2005). Additionally, the gas bubble velocity is taken into account, thereby increasing the accuracy of the pressure drop predictions compared to those of the model of Kreutzer et al. Experimental data were obtained for nitrogen-water Taylor flow in a round glass channel with an inner diameter of 250 mu m. The capillary number Ca (gl) varied between 2.3 x 10(-3) and 8.8 x 10(-3) and the Reynolds number Re (gl) varied between 41 and 159. The presented model describes the experimental results with an accuracy of +/- 4% of the measured values.

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We have observed extreme-ultraviolet (XUV) ''line-free'' continuum emission from laser plasmas of high atomic number elements using targets irradiated with 248 nm laser pulses of 7 ps duration at a power density of similar to 10(13) W/cm(2). Using both dispersive spectroscopy and streak camera detection, the spectral and temporal evolution of XUV continuum emission for several target atomic numbers has been measured on a time scale with an upper limit of several hundred picoseconds limited by amplified spontaneous emission. (C) 1997 American Institute of Physics.