Estudos sobre a nutriçao mineral do arroz: XXVII . Fatores que influenciam a absorção radicular do fósforo pela variedade IAC-164

Within the range of 15 to 240 minutes it was found that absorption increased in a linear fashion.By varying the external concentration of H2PO-4 from 10-7M to 10-2 M a dual pattern uptake was observed: a high affinity macnamism with a Km= 6.17 x 10-6M and a second one with low affinity (Km= 1.64 x 10-2M) . Absorption was raised when the external concentration of Mg ions varied from 10-6 to 10-4When supplied in the range of 10-6 to 10-2M the chloride salis of K and Ca rediced the absorption, the effect being traced to the CI ion. Zincsulfate (10-8to 10-4M) had no effect on phosphate absorption.Na faixa de 15 a 240 minutos a absorção do fósforo marcado com P32 é crescente e linear. A variação na concentração externa de H2PO4 mostrou existirem duas isotermas, uma operando em baixas concentrações (Km = 6,17x10-6M) e outra correspondente a altas concentrações (Km = 1,64x10-2M). Oíon magnésio aumenta a absorção e o Cl- causa diminuição quando fornecido na concentração de 10-2m.SO4-2e Zn+2 não mostraram efeito

Cluster scaling and its redshift evolution from XMM-Newton

We put together the results of XMM-Newton observations of a number of representative group and cluster samples at low and high redshifts. These results confirm the entropy ramp as an explanation of the observed scaling relations. We observe a mild evolution in the entropy of clusters. The observed degree of evolution is consistent with expectations of the shock heating at a fixed overdensity (500) with respect to the critical density in LCDM. The study of the evolution in the pressure scaling imposes strong requirements in the definition of the average temperature of the cluster. The scaling temperature should be consistent to better than the 10% level. Once such a consistency is achieved, no additional evolution in the pressure has been detected in addition to the prediction of the shock heating in the LCDM Universe.Comment: 8 pages, Adv. in Space Research, in pres

Hospitais: espaços de cura e lugares de memória da saúde

O presente artigo pretende analisar o Hospital Gaffrée e Guinle, construído na década de 1920, na cidade do Rio de Janeiro, em um processo de tomada de controle, pela administração pública, da gestão da assistência hospitalar na capital federal. Esse hospital representa o encontro da filantropia com um projeto de saúde pública posto em prática no Distrito Federal à mesma época. A instituição sintetiza também o desenvolvimento da medicina e sua tradução na arquitetura hospitalar, bem como a efervescência intelectual do período, mais especificamente das idéias nacionalistas, interpretadas tanto na escolha do estilo arquitetônico - o neocolonial - quanto na questão da salvação da raça através do combate e controle da sífilis.This paper analyzes the Gaffrée & Guinle Hospital, built in Rio de Janeiro during the 1920s as the result of a process whereby the government took over the management of hospital care in the federal capital. The hospital is the point of convergence between philanthropy and a public healthcare project implemented in the Federal District at that time. It also synthesizes the development of medicine and how the latter translates into hospital architecture, as well as the intellectual effervescence at the time, more specifically the nationalist ideas which can be identified both in the choice of architectural style - namely the neocolonial - and in the theme of salvation of a race through the combat and control of syphilis

Electronic Structure And Origin Of Ferromagnetism In Ga 1-xmnxas Semiconductors

We perform a detailed theoretical study, within the density-functional theory, of the electronic structure and magnetic properties of Ga 1-xMnxAs diluted semiconductors. Ab initio total energy results provide evidence that the appearance of a ferromagnetic state in these materials is due to an exchange coupling between the localized ↑ S=52 Mn spins mediated by quasi-localized ↓ holes, with strong p-like character, surrounding the fully polarized Mn d5-electrons. From total energy differences, we find the effective Mn-Mn coupling always ferromagnetic, with the Mn-Mn interaction intermediated by an antiferromagnetic coupling of each Mn spin to the holes. © 2003 Elsevier B.V. All rights reserved.340-342874877Ohno, H., (1992) Phys. Rev. Lett., 68, p. 2664Ohno, H., (1996) Appl. Phys. Lett., 69, p. 363Matsukura, F., (1998) Phys. Rev. B, 57, pp. R2037Ohno, H., (1999) J. Magn. Magn. Mater., 200, p. 110Edmonds, K.W., (2002) Appl. Phys. Lett., 81, p. 3010Seong, M.J., (2002) Phys. Rev. B, 66, p. 033202Potashnik, S.J., (2001) Appl. Phys. Lett., 79, p. 1495Van Esch, A., (1997) Phys. Rev. B, 56, p. 13103Asklund, H., (2002) Phys. Rev. B, 66, p. 115319Yu, K.M., (2002) Phys. Rev. B, 65, pp. R201303Yu, K.M., (2002) Appl. Phys. Lett., 81, p. 844Moriya, R., Munekata, H., (2003) J. Appl. Phys., 93, p. 4603Potashnik, S.J., (2002) Phys. Rev. B, 66, p. 012408Hayashi, T., (2001) Appl. Phys. Lett., 78, p. 1691Dietl, T., (1997) Phys. Rev. B, 55, pp. R3347Ohno, H., Matsukura, F., (2001) Solid State Commun., 117, p. 179Vanderbilt, D., (1990) Phys. Rev. B, 41, p. 7892Kresse, G., Hafner, J., (1993) Phys. Rev. B, 47, pp. R558Kresse, G., Furthmuller, J., (1996) Phys. Rev. B, 54, p. 11169Kresse, G., Joubert, D., (1999) Phys. Rev. B, 59, p. 1758Chapman, R.A., Hutchinson, W.G., (1967) Phys. Rev. Lett., 18, p. 443Schneider, J., (1987) Phys. Rev. Lett., 59, p. 240Linnarsson, M., (1997) Phys. Rev. B, 55, p. 6938Singley, E.J., (2002) Phys. Rev. Lett., 89, p. 097203Dietl, T., (2001) Phys. Rev. B, 63, p. 195205Abolfath, M., (2001) Phys. Rev. B, 63, p. 054418Zhao, Y.-J., (2003) Phys. Rev. Lett., 90, p. 04720

First Principles Study Of The Ferromagnetism In Ga1-xmn Xas Semiconductors

We have performed ab initio calculations within the density-functional theory for Ga1-xMnxAs As diluted semiconductors. Total energy results unambiguously show that a quasi-localized ↓ hole, with predominant p-like character, surrounds the fully polarized Mn ↑ d 5-electrons. The calculations indicate that the holes form a relatively dispersionless impurity band, thus rendering effectivemass descriptions of hole states open to challenge. We obtain estimates both for the s = 1/2 hole and S = 5/2 Mn exchange coupling, and for the distance dependence of the effective Mn-Mn exchange interaction. The results demonstrate that the effective Mn-Mn coupling is always ferromagnetic, and thus non-RKKY, and is intermediated by the antiferromagnetic coupling of each Mn spin to the holes.164682438250Ohno, H., Munekata, H., Penney, T., Von Molnàr, S., Chang, L.L., (1992) Phys. Rev. Lett., 68, p. 2664Ohno, H., Shen, A., Matsukura, F., Oiwa, A., Endo, A., Katsumoto, S., Iye, Y., (1996) Appl. Phys. Lett., 69, p. 363Van Esch, A., Van Bockstal, L., De Boeck, J., Verbanck, G., Van Steenbergen, A.S., Wellmann, P.J., Grietens, B., Borghs, G., (1997) Phys. Rev. B, 56, p. 13103Matsukura, F., Ohno, H., Shen, A., Sugawara, Y., (1998) Phys. Rev. B, 57, pp. R2037Ohno, H., (1999) J. Magn. Magn. Mater., 200, p. 110Potashnik, S.J., Ku, K.C., Chun, S.H., Berry, J.J., Samarth, N., Schiffer, P., (2001) Appl. Phys. Lett., 79, p. 1495Edmonds, K.W., Wang, K.Y., Campion, R.P., Neumann, A.C., Foxon, C.T., Gallagher, B.L., Main, P.C., (2002) Appl. Phys. Lett., 81, p. 3010Seong, M.J., Chun, S.H., Cheong, H.M., Samarth, N., Mascarenhas, A., (2002) Phys. Rev. B, 66, p. 033202Asklund, H., Iliver, L., Kanski, J., Sadowski, J., (2002) Phys. Rev. B, 66, p. 115319Yu, K.M., Walukiewicz, W., Wojtowicz, T., Kuryliszyn, I., Liu, X., Sasaki, Y., Furdyna, J.K., (2002) Phys. Rev. B, 65, pp. R201303Yu, K.M., Walukiewicz, W., Wojtowicz, T., Lim, W.L., Liu, X., Sasaki, Y., Dobrowolska, M., Furdyna, J.K., (2002) Appl. Phys. Lett., 81, p. 844Potashnik, S.J., Ku, K.C., Mahendiran, R., Chun, S.H., Wang, R.F., Samarth, N., Schiffer, P., (2002) Phys. Rev. B, 66, p. 012408Moriya, R., Munekata, H., (2003) J. Appl. Phys., 93, p. 4603Dos Santos, R.R., Oliveira, L.E., D'Albuquerque e Castro, J., (2002) J. Phys.: Condens. Matter, 14, p. 3751Dos Santos, R.R., Oliveira, L.E., D'Albuquerque e Castro, J., (2003) J. Appl. Phys., 93, p. 1845Hayashi, T., Hashimoto, Y., Katsumoto, S., Iye, Y., (2001) Appl. Phys. Lett., 78, p. 1691Dietl, T., Haury, A., Merle D'Aubigné, Y., (1997) Phys. Rev. B, 55, pp. R3347Ohno, H., Matsukura, F., (2001) Solid State Commun., 117, p. 179Okabayashi, J., Kimura, A., Rader, O., Mizokawa, T., Fujimori, A., Hayashi, T., Tanaka, M., (2001) Phys. Rev. B, 64, p. 125304Singley, E.J., Kawakami, R., Awschalom, D.D., Basov, D.N., (2002) Phys. Rev. Lett., 89, p. 097203Dietl, T., Ohno, H., Matsukura, F., (2001) Phys. Rev. B, 63, p. 195205Abolfath, M., Jungwirth, T., Brum, J., MacDonald, A.H., (2001) Phys. Rev. B, 63, p. 054418Sanvito, S., Ordejón, P., Hill, N.A., (2001) Phys. Rev. B, 63, p. 165206Bouzerar, G., Kudrnovský, J., Berqvist, L., Bruno, P., (2003) Phys. Rev. B, 68, pp. 081203RSandratskii, L.M., Bruno, P., (2002) Phys. Rev. B, 66, p. 13443522nd Int. Conf. on Defects in Semiconductors (Aarhus, Denmark, 2003), , Preliminary results were presented at theDa Silva, A.J.R., Fazzio, A., Dos Santos, R.R., Oliveira, L.E., (2003) Physica B, 340-342, p. 874Vanderbilt, D., (1990) Phys. Rev. B, 41, p. 7892Kresse, G., Hafner, J., (1993) Phys. Rev. B, 47, pp. R558Kresse, G., Furthmüller, J., (1996) Phys. Rev. B, 54, p. 11169Kresse, G., Joubert, D., (1999) Phys. Rev. B, 59, p. 1758Linnarsson, M., Janzén, E., Monemar, B., Kleverman, M., Thilderkvist, A., (1997) Phys. Rev. B, 55, p. 6938Chapman, R.A., Hutchinson, W.G., (1967) Phys. Rev. Lett., 18, p. 443Schneider, J., Kaufmann, U., Wilkening, W., Baeumler, M., Kohl, F., (1987) Phys. Rev. Lett., 59, p. 240Zhao, Y.-J., Mahadevan, P., Zunger, A., (2004) Appl. Phys. Lett., 84, p. 3753Zhao, Y.-J., Shishidou, T., Freeman, A.J., (2003) Phys. Rev. Lett., 90, p. 047204Sanyal, B., Bengone, O., Mirbt, S., (2003) Phys. Rev. B, 68, p. 20521

N-terminal domain of human Hsp90 triggers binding to the co-chaperone p23

The molecular chaperone Hsp90 is a protein folding machine that is conserved from bacteria to man. Human, cytosolic Hsp90 is dedicated to folding of chiefly signal transduction components. The chaperoning mechanism of Hsp90 is controlled by ATP and various cochaperones, but is poorly understood and controversial. Here, we characterized the Apo and ATP states of the 170-kDa human Hsp90 full-length protein by NMR spectroscopy in solution, and we elucidated the mechanism of the inhibition of its ATPase by its cochaperone p23. We assigned isoleucine side chains of Hsp90 via specific isotope labeling of their δ-methyl groups, which allowed the NMR analysis of the full-length protein. We found that ATP caused exclusively local changes in Hsp90’s N-terminal nucleotide-binding domain. Native mass spectrometry showed that Hsp90 and p23 form a 2∶2 complex via a positively cooperative mechanism. Despite this stoichiometry, NMR data indicated that the complex was not fully symmetric. The p23-dependent NMR shifts mapped to both the lid and the adenine end of Hsp90’s ATP binding pocket, but also to large parts of the middle domain. Shifts distant from the p23 binding site reflect p23-induced conformational changes in Hsp90. Together, we conclude that it is Hsp90’s nucleotide-binding domain that triggers the formation of the Hsp902p232 complex. We anticipate that our NMR approach has significant impact on future studies of full-length Hsp90 with cofactors and substrates, but also for the development of Hsp90 inhibiting anticancer drugs