Browsing by Author "CHUAQUI, R"
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- ItemAN ELEMENTARY GEOMETRIC NONSTANDARD PROOF OF THE JORDAN CURVE THEOREM(1994) BERTOGLIO, N; CHUAQUI, RWe give an elementary proof, using nonstandard analysis, of the Jordan curve theorem. We also give a nonstandard generalization of the theorem. The proof is purely geometrical in character, without any use of topological concepts and is based on a discrete finite form of the Jordan theorem, whose proof is purely combinatorial.
- ItemAPPROXIMATION TO TRUTH AND THEORY OF ERRORS(1985) CHUAQUI, R; BERTOSSI, L
- ItemFREE-VARIABLE AXIOMATIC FOUNDATIONS OF INFINITESIMAL ANALYSIS - A FRAGMENT WITH FINITARY CONSISTENCY PROOF(1995) CHUAQUI, R; SUPPES, P
- ItemHISTOLOGIC ASSESSMENT OF THE AGE OF RECENT BRAIN INFARCTS IN MAN(1993) CHUAQUI, R; TAPIA, JIn order to design a dating system based on the microscopic picture of brain infarcts of recent onset, we performed the histological examination of 31 infarcts covering the first 4 weeks of evolution in 30 autopsy cases. The date of the cerebral vascular accident was clinically established in every case. There were 13 men and 17 women with a mean age of 65 years. Hemorrhagic infarcts were found in 15 cases and anemic infarcts in 16 cases. Based on the histological features four periods were identified: the first period, from day 1 through day 4, was characterized by the predominance of eosinophilic neurons and necrotic oligodendrocytes; the second period, from day 5 through day 7, differed from the first by the appearance of macrophages and of newly formed blood vessels; the third period, from day 8 through day 14, showed neuronal ghosts, macrophages, astrocytic proliferation, gemistocytes, and absence of neutrophils; and in the fourth period, from day 15 through day 27, there were no eosinophilic neurons, and neither necrotic oligodendrocytes nor myelin in the central portion of the infarct were identified. By assessing the histological features and accurately correlating the findings with the corresponding clinical data, we have been able to describe four distinct microscopic pattems of the first month of evolution of brain infarcts. The present findings may be considered useful morphological clues to better characterize the early evolutional phase of brain infarcts in humans.
- ItemINTESTINAL MICROSPORIDIOSIS IN A CHILEAN PATIENT WITH ACQUIRED-IMMUNODEFICIENCY-SYNDROME (AIDS)(1993) ODDO, D; CHUAQUI, R; HOFFMANN, E; GARCIA, MA 24-year-old male patient with AIDS diagnosed in 1989, and with several episodes of pneumocystosis, was admitted because of a chronic diarrheic syndrome and severe epigastric pain.
- ItemMENINGOTHELIAL MENINGIOMA WITH AMIANTHOID FIBERS - CASE-REPORT WITH ULTRASTRUCTURAL-STUDY(GUSTAV FISCHER VERLAG, 1992) CHUAQUI, R; GONZALEZ, S; TORREALBA, GThe case of a meningothelial meningioma with 'amianthoid' fibers in a 48-year-old woman is presented. By light microscopy the tumor showed the typical features of meningothelial meningioma and rounded, deeply eosinophilic, and fibrillary areas, especially around and/or in the vicinity of blood vessels. These fibers are also called 'amianthoid' fibers. Ultrastructurally, these foci were made up of disorderly arranged and interwaving mature collagen fibrils with a variable width between 40 and 190 nm. No evidence of intracellular collagen synthesis by the tumor cells was found. The presence of 'amianthoid' fibers does not seem to carry any prognostic significance.
- ItemPLACENTAL ALTERATIONS AND INTRAUTERINE GROWTH-RETARDATION ASSOCIATED WITH ENALAPRIL EXPOSURE IN EARLY, MID, AND LATE PREGNANCY IN THE RAT(1993) VALDES, G; CHUAQUI, R; CORTHORN, J; DUARTE, IObjective: To identify the stage of placental development in which enalapril use in the pregnant rat is deleterious.
- ItemPLACENTAL ALTERATIONS, INTRAUTERINE GROWTH-RETARDATION AND TERATOGENICITY ASSOCIATED WITH ENALAPRIL USE IN PREGNANT RATS(1992) VALDES, G; MARINOVIC, D; FALCON, C; CHUAQUI, R; DUARTE, IEnalapril (15 mg/kg/day p.o.) was given to 11 pregnant rats from day 1 to 9 (E1-9) and to 11 rats from day 10 to 20 (E10-20) of pregnancy; 12 rats were the control group. Fifteen animals were sacrificed on day 20 of pregnancy and 19 were allowed to progress into partum. Placentas were smaller in E10-20 rats (-15%, p < 0.05) and had a simple hypocellular cordonal structure; in E1-9 animals the predominant pattern was a combination of complex and simple structure. At day 20 the fetuses in the treated groups were smaller than the controls (-5% in E1-9 and -16% in E10-20, p < 0.05); differences disappeared on the 13th day postpartum. Two fetuses from treated mothers presented incomplete skull ossification. We believe this report adds arguments to preclude converting enzyme inhibitors in pregnancy.
- ItemPRAGMATIC TRUTH AND APPROXIMATION TO TRUTH(ASSN SYMBOLIC LOGIC INC, 1986) MIKENBERG, I; DACOSTA, NCA; CHUAQUI, R
- ItemPREORDERINGS COMPATIBLE WITH PROBABILITY-MEASURES(1983) CHUAQUI, R; MALITZ, J
- ItemSENTENCES OF TYPE THEORY - THE ONLY SENTENCES PRESERVED UNDER ISOMORPHISMS(CAMBRIDGE UNIV PRESS, 1991) MARSHALL, MV; CHUAQUI, R
- ItemTHE GEOMETRY OF LEGAL PRINCIPLES(1991) CHUAQUI, R; MALITZ, J
- ItemTYPES IN CLASS SET THEORIES(1985) REINHARDT, WN; CHUAQUI, R