Problemas da evolução geomorfológica quaternaria do noroeste de Portugal

[Resumen] El relieve del Minho occidental se caracteriza por la presencia de valles muy amplios que forman una superficie poligéniaa de edad probablemente Plioaeno-cuaternaria. Esta superficie es constitu{da por una plataforma marina al oeste y por alveolos de erosión diferencial hacia el interior en los que se produjo una importante acumulación de terrazas y glacis durante el Cuaternario. Estes valles se apertan.bruscamente en e1 pie de las altas plataformas interiores. También al sur del rto Ave los valles de los cursos fluviales son estrechos y siguen encajados en la plataforma litoral calabriana. Se discute las causas petrográficas, climáticas y teotónicas de estos oontrastes y se estudia especialmente las terrazasy glacis existentes en los valles de los ríos Miño ~ Lima y Cávado.[Resumo] O relevo do baixo Minho apresenta unha acentuada originalidade que resulta da existencia de unha superficie poligéniaca de idade provavelmente Plio-quaternária desenvolvida ao longo dos rios principais. Os cursos de água correm nela ao rés do solo contrastando fortemente como brutal encaixe que apresentam no sopé oeidental das montanhas interiores. um aontraste acentuado desenhase também em relaçao ao litoral ao sul do rio Ave onde os rios entalham profundas gargantas nunha plataforma calabriana. Sao discutidas as causas de ordem petrográfica, climática e tectónica destes contrastes dandose particular atençao ao significado dos terraços e dos glacis que ocorrem ao longo do Minho do Lima e do Cavado

The Quaternary in the Hesperian Massif in Portugal. Problems of its Geological and Geomorphological Study

The major problem in studying the Quaternary in the Hesperian Massif in Portugal is unquestionably posed by the scarcity ofdeposits, faunas and floras, which makes it difficult to establish a more or less accurate chrono-stratigraphy. The Hesperian Massif is a morpho-structural unit in a regime of tectonic uplifting and for that reason erosion in it clearly prevails over sedimentation. Accordingly, studies ofthe Quaternary in Portugal inevitably tend to concentrate on the coastal regions and on the vestibular sectors of valleys, where existing beaches, terraces and caves display a sizeable palaeontological and archaeological spoil. Also inevitably have of late the upper Pleistocene and above all the Holocene been at the heart of the most remarkable advance in knowledge, because not only of more abundant vestiges but also of the easier achievement of an absolute chronology based on radiocarbon. One problem which immediately arises is the very question ofthe dividing line between the Tertiary and the Quaternary. Traditionally, and in the absence of more reliable indicators, that dividing line has been defined inland through the raña deposits, and on the littoral 00 the basis of forms and deposits to which a Calabrian age has been normally ascribed. Rañas are, however, rigorously azoic deposits; ofthem it is known only that they constitute the more recent deposits of large planation surfaces in the Hesperian Massif and that they precede the entrenchment of valleys and the formation of fluvial terraces linked to well organized drainage axes. On the other hand, recent research has produced dissimilar, sometimes contradictory results concerning the genesis (either marine or fluvial) of the earliest deposits in the littoral platform, and from the age point ofview the least uncontroversial vestige, in the sites ofmore complete stratigraphy, is that of the occurrence of a Placenzian transgressive phase. From the upper Pleistocene onwards there begins to exist, chiefly on coastal regions, a certain wealth and variety ofsediments, and ofarchaeological spoil as well. Because of the acid nature of the soils and deposits, however, faunistic vestiges continue to be scarce; and that fact, together with the difficulty of obtaining alternative absolute datings, makes it aleatory to establish a chronostratigraphy - with the exception, to sorne extent and as noted aboye, ofdatings pertaining to the Holocene. Inland, the unavailability or paucity ofcorrelative deposits has irremediably affected the studies of Quaternary morphogenesis. Nevertheless, the application ofgeomorphological criteria, linking them to the few deposits available, has rendered sorne progress possible, namely in the domain ofneotectonics. Another domain in which significant progress has been made is the study of glacial and periglacial manifestations, especiaHy by combining meticulous field observations with laboratory study ofthe deposits. An instance ofthat is the analysis, recently carried out, ofthe glaciation vestiges in Serra do Geres-Xurés, which has clarified the importance ofcold climates in the late Quaternary morphogenesis in the mountains of northern Portugal and southern Galicia. The major future advances in the knowledge of the Quaternary geology and geomorphology in Portu gal wiH have to be founded on the foHowing premises: 1) the study ofthe submersed deposits ofthe Continental platform; 2) the study ofthe weathering and soils which have developed both in the emersed deposits and in the rock substratum; 3) the minute cartography of the deposits and the establishment of a rigorous lithostratigraphy of those deposits in the most representative sites; 4) the laboratory analysis of the deposits, namely studies of micromorphology; 5) the utilization of aH the available data to establish a relative chronology (fauna, flora, lithic industry and other archaeological vestiges) and, aboye aH, the application of the several possible methods of absolute dating (radiocarbon, thermoluminescence, amino-acids, palaeomagnetism); 6) the study of erosive forms, to different scales, and the attempt to establish a morphogenetic and chronological correlation with the known deposits, weathering and soils; 7) the development ofinterdisciplinary research focused upon the more promising problems and sites; 8) the integration of results, targeted at palaeoenvironmental reconstitution

Magnetoexcitons And Correlated Electrons In Quantum Dots In A Magnetic Field

Magnetoexcitons interacting with strongly correlated electronic states in quantum dots in a strong magnetic field are studied. Exact calculations relate the absorption and emission of few-electron artificial atoms to magnetic-field-induced phase transitions between "magic" states. For large compact droplets, the coupling of magnetoexcitons to low-energy excitations (edge magnetorotons) leads to a strong enhancement of the oscillator strength at the Fermi level (Fermi edge singularity) both in absorption and in emission on acceptors. The condensation of edge magnetorotons signals the reconstruction of the droplet and is accompanied by different structures in the absorption spectrum.54161139711409Kastner, M., (1993) Phys. Today, 24 (1), p. 24Chakraborty, T., (1992) Comments Condens. Matter Phys., 16, p. 35Petroff, P.M., Denbaars, S.P., (1994) Superlatt. Microstruct., 15, p. 15Drexler, H., Leonard, D., Hansen, W., Kotthaus, J.P., Petroff, P.M., (1994) Phys. Rev. Lett., 73, p. 2252Wojs, A., Hawrylak, P., (1995) Phys. Rev. B, 51, p. 10880Ashoori, R.C., Stormer, H.L., Weiner, J.S., Pfeiffer, L.N., Baldwin, K.W., West, K.W., (1993) Phys. Rev. Lett., 71, p. 613Su, B., Goldman, V.J., Cunningham, J.E., (1992) Science, 255, p. 313Hawrylak, P., (1993) Phys. Rev. Lett., 71, p. 3347De Chamon, C., Wen, X.-G., (1994) Phys. Rev. B, 49, p. 8227Palacios, J.J., (1993) Europhys. Lett., 23, p. 495(1995) Phys. Rev. B, 51, p. 2363MacDonald, A.H., Eric Yang, S.R., Johnson, M.D., (1993) Aust. J. Phys., 46, p. 345Klein, O., (1995) Phys. Rev. Lett., 74, p. 785Kane, C.L., Fisher, M.P.A., Polchinski, J., (1994) Phys. Rev. Lett., 72, p. 4129Maksym, P.A., (1993) Physica B, 184, p. 385Maksym, P.A., Chakraborty, T., (1990) Phys. Rev. Lett., 65, p. 108(1992) Phys. Rev. B, 45, p. 1947Palacios, J.J., Martin-Moreno, L., Chiappe, G., Louis, E., Tejedor, C., (1994) Phys. Rev. B, 50, p. 5760(1995) Phys. Rev. Lett., 74, p. 5120Apalkov, V.M., Rashba, E.I., (1995) Solid State Commun., 93, p. 193Chen, X.M., Quinn, J.J., (1994) Phys. Rev. B, 50, p. 2354MacDonald, A.H., (1992) Phys. Rev. Lett., 68, p. 1939Buchmann, H., (1990) Phys. Rev. Lett., 65, p. 1056Turb-erfield, A.J., (1990) Phys. Rev. Lett., 65, p. 637Goldberg, B.B., (1990) Phys. Rev. Lett., 65, p. 641Hawrylak, P., (1991) Phys. Rev. B, 44, p. 3821Uneyama, T., Sham, L.J., (1990) Phys. Rev. Lett., 65, p. 1048Hawrylak, P., Pfannkuche, D., (1993) Phys. Rev. Lett., 70, p. 485Pfannkuche, D., (1994) Solid State Electron., 37, p. 1221Apalkov, V.M., Rashba, E.I., (1991) Pis'ma Zh. Éksp. Teor. Fiz., 53, p. 420(1991) JETP Lett., 53, p. 442Hawrylak, P., (1992) Phys. Rev. B, 45, p. 4237Hawrylak, P., Pulsford, N., Ploog, K., (1993) Phys. Rev. B, 46, p. 15593(1992) Solid State Commun., 81, p. 525Petrou, A., Smith, M.C., Perry, C.H., Worlock, J.M., Aggarwal, R.L., (1984) Solid State Commun., 52, p. 93Kukushkin, I.V., Klitzing, K.V., Ploog, K., Timofeev, V.B., (1990) Phys. Rev. B, 40, p. 7788Plaut, A.S., Lage, H., Grambow, P., Heitmann, D., Von Klitzing, K., Ploog, K., (1991) Phys. Rev. Lett., 67, p. 1642Buhmann, H., Joss, W., Von Klitzing, K., Kukushkin, I.V., Martinez, G., Plaut, A.S., Ploog, K., Timofeev, V.B., (1990) Phys. Rev. Lett., 65, p. 1056Buhmann, H., Joss, W., Von Klitzing, K., Kukushkin, I.V., Plaut, A.S., Martinez, G., Ploog, K., Timofeev, V.B., (1991) Phys. Rev. Lett., 66, p. 926Kukushkin, I.V., Pulsford, N.J., Von Klitzing, K., Ploog, K., Haug, R.J., Koch, S., Timofeev, V.B., (1992) Phys. Rev. B, 45, p. 4532Stone, M.D., Wyld, H.W., Schult, R.L., (1992) Phys. Rev. B, 45, p. 14156Stone, M.D., (1990) Int. J. Mod. Phys., 5, p. 503Kallin, C., Halperin, B.I., (1985) Phys. Rev. B, 31, p. 3635Wu, J.-W., Hawrylak, P., Quinn, J.J., (1985) Phys. Rev. B, 31, p. 6592Hawrylak, P., (1995) Phys. Rev. B, 51, p. 1770

Preliminary results on the Gaulish terra sigillata from the fish-salting production centre at Tróia

The fish-salting production centre at Troia received various imports of terra sigillata from the 1st century to the 6th century. Although it did not reach the significance of the African Red Slip Ware, Gaulish Sigillata is the second most important group of imports of this category on this archaeological site. The recognition of a Tiberian foundation level with Gaulish vessels dates the arrival of this tableware. Nevertheless, we agree with the assumption of previous studies that the majority of the pieces from this assemblage corresponds to the Claudian period onwards. The purpose of this paper is to present the current state regarding terra sigillata studies at Troia, more precisely related to the Gaulish productions and their significance in the largest fish-salting centre of the Roman Empire.O centro de produção de salgas de peixe de Troia recebeu inúmeras importações de terra sigillata entre o século I d.C. e o século VI d.C. Ainda que não tenha atingido a proporção da terra sigillata africana, a terra sigillata gálica é o segundo maior grupo de importação desta categoria neste sítio arqueológico. A identificação de um nível de fundação tiberiano com taças gálicas data a chegada desta cerâmica de mesa. Não obstante, validamos as conclusões obtidas em estudos anteriores que referem que a maioria das peças desta colecção deverá ser integrada a partir do período cláudio. O objectivo deste artigo é apresentar o estado actual dos estudos de terra sigillata de Troia, mais precisamente as produções gaulesas e o seu significado no maior centro de produção de salgas de peixe do Império Romano.info:eu-repo/semantics/publishedVersio

Dihydrotestostenone increase the gene expression of androgen receptor coregulator FHL2 in human nontransformed epithelial prostatic cells

The actions of androgens are mediated through an androgen receptor (AR), and AR activity is modulated by coregulators. The aim of this study was to assess the action of androgens in the expression of AR and the coregulators FHL-2 and SHP-1 in human non-transformed epithelial prostatic cells (HNTEP) treated with androgens. Prostate tissues were obtained from 12 patients between 60 and 77 years of age. HNTEP cells were grown in basal medium and treated with DHT in different conditions. HNTEP cells under treatment with DHT (10-13 M) induced an increase in FHL-2 expression. In turn, high DHT concentrations (10-8 M) induced an increase in the expression SHP-1. The present data suggest that the SHP-1 and FHL-2 genes play a role in the control of responsiveness and androgen-dose-dependent cell proliferation in HNTEP cells. Further studies are needed to assess the influence of androgens in AR and its coregulators and the implications in the pathophysiology of prostate diseases.Key words: Androgens, FHL-2, AR, prostate, proliferation, coregulators