Pulmonary gas exchange and acid-base state at 5,260 m in high-altitude Bolivians and acclimatized lowlanders

[EN] Pulmonary gas exchange and acid-base state were compared in nine Danish lowlanders (L) acclimatized to 5,260 m for 9 wk and seven native Bolivian residents (N) of La Paz (altitude 3,600-4,100 m) brought acutely to this altitude. We evaluated normalcy of arterial pH and assessed pulmonary gas exchange and acid-base balance at rest and during peak exercise when breathing room air and 55% O2. Despite 9 wk at 5,260 m and considerable renal bicarbonate excretion (arterial plasma HCO3- concentration = 15.1 meq/l), resting arterial pH in L was 7.48 +/- 0.007 (significantly greater than 7.40). On the other hand, arterial pH in N was only 7.43 +/- 0.004 (despite arterial O2 saturation of 77%) after ascent from 3,600-4,100 to 5,260 m in 2 h. Maximal power output was similar in the two groups breathing air, whereas on 55% O2 only L showed a significant increase. During exercise in air, arterial PCO2 was 8 Torr lower in L than in N (P < 0.001), yet PO2 was the same such that, at maximal O2 uptake, alveolar-arterial PO2 difference was lower in N (5.3 +/- 1.3 Torr) than in L (10.5 +/- 0.8 Torr), P = 0.004. Calculated O2 diffusing capacity was 40% higher in N than in L and, if referenced to maximal hyperoxic work, capacity was 73% greater in N. Buffering of lactic acid was greater in N, with 20% less increase in base deficit per millimole per liter rise in lactate. These data show in L persistent alkalosis even after 9 wk at 5,260 m. In N, the data show 1) insignificant reduction in exercise capacity when breathing air at 5,260 m compared with breathing 55% O2; 2) very little ventilatory response to acute hypoxemia (judged by arterial pH and arterial PCO2 responses to hyperoxia); 3) during exercise, greater pulmonary diffusing capacity than in L, allowing maintenance of arterial PO2 despite lower ventilation; and 4) better buffering of lactic acid. These results support and extend similar observations concerning adaptation in lung function in these and other high-altitude native groups previously performed at much lower altitudes.

Search for K isomers in 252,254 No and 260 Sg and investigation of their nuclear structure

Study of K isomerism in the transfermium region around the deformed shells at N=152, Z=102, and N=162, Z=108 provides important information on the structure of heavy nuclei. Recent calculations suggest that the K-isomerism can enhance the stability of such nuclei against alpha emission and spontaneous fission. Nuclei showing K isomerism have neutron and proton orbitals with large spin projections on the symmetry axis which is due to multi quasiparticle states with aligned spins K. Quasi-particle states are formed by breaking pairs of nucleons and raising one or two nucleons in orbitals near the Fermi surface above the gap, forming high K (multi)quasi-particle states mainly at low excitation energies. Experimental examples are the recently studied two quasi-particle K isomers in 250,256-Fm, 254-No, and 270-Ds. Nuclei in this region, are produced with cross sections ranging from several nb up to µb, which are high enough for a detailed decay study. In this work, K isomerism in Sg and No isotopes was studied at the velocity filter SHIP of GSI, Darmstadt. The data were obtained by using a new data acquisition system which was developed and installed during this work. 252,254-No and 260-Sg were produced in fusion evaporation reactions of 48-Ca and 54-Cr projectiles with 206,208-Pb targets at beam energies close to the Coulomb barrier. A new K isomer was discovered in 252-No at excitation energy of 1.25 MeV, which decays to the ground state rotational band via gamma emission. It has a half-life of about 100 ms. The population of the isomeric state was about 20% of the ground state population. Detailed investigations were performed on 254-No in which two isomeric states (275 ms and 198 µs) were already discovered by R.-D. Herzberg, but due to the higher number of observed gamma decays more detailed information about the decay path of the isomers was obtained in the present work. In 260-Sg, we observed no statistically significant component with a half life different from that of the ground state. A comparison between experimental results and theoretical calculations of the single particle energies shows a fair agreement. The structure of the here studied nuclei is in particular important as single particle levels are involved which are relevant for the next shell closure expected to form the region of the shell stabilized superheavy elements at proton numbers 114, 120, or 126 and neutron number 184. K isomers, in particular, could be an ideal tool for the synthesis and study of these isotopes due to enhanced spontaneous fission life times which could result in higher alpha to spontaneous fission branching ratios and longer half lifes.

260 Revolutionshelden : zur Erinnerung u. zum Nachdenken dem Reichspräsidenten Fritz Ebert u. d. deutschen Volke gewidment

von Ernst Rademacher

Na 1 Nachlass Max Horkheimer, 260 - Korrespondenzen u.a. mit dem Direktor der Stadt- und Unibibliothek Frankfurt am Main Professor Clemens Köttelwesch (p. V 66, 138-320)

2 Briefe zwischen F. Champion Ward und Max Horkheimer, 1967; 1 Brief von Max Horkheimer an John Slawson, 1962; 21 Briefe zwischen dem Direktor der Stadt- und Unibibliothek Frankfurt am Main Professor Clemens Köttelwesch und Max Horkheimer, 1956-; 1 Brief an Hertha Dembitzer, 1974; 1 Brief von Hertha Dembitzer, 1974; Schenkungsbrief 1956; Hertha Dembitzer: 2 Briefe zwischen Hertha Dembitzer und Clemens Köttelwesch, 1974;

Na 50 Nachlass Arthur Schopenhauer - 'Schopenhauer-Archiv', 260 - Zwischenmitteilung über das Fehlen der Güterschen Quittungen

1 Seite

Ein Aquarienfisch vor 260 Jahren

Von Wolfgang Bötticher

Ms.Ff.F.Stoltze 3. 260 - Brief von Alois J. Ruckert an Friedrich Stoltze

"Der warme Deckel", Übertragung ins Fränkische

Na 1 Nachlass Max Horkheimer, 594 - Korrespondenzen mit Friedrich (Frederick) Pollock (p. VI 40, 1-260)

2 Briefe zwischen Gilbert Lazerus und Max Horkheimer, 1960; 1 Brief von dem NDR Studio (Berlin) an Max Horkheimer, 05.09.1960; 1 Brief von Frederick Pollock an H. Meng, 19.05.1960; 1 Brief von Max Horkheimer an die University of Chicago, [1960]; 1 Brief von Max Horkheimer an die Hermann Weil Memorial Foundation (New York), 01.04.1960;

Ms. lat. oct. 260 - Venezianische Relazionen und Akten. Flugschriften

Die Foliierung geht nur bis Bl. 475; zusätzlich gibt es das Blatt 323a

Dead Sea lake level for the last 260 ka

The rain regime of the Levant during the late Quaternary was controlled primarily by Mediterranean cyclonic systems associated with North Atlantic climate shifts. Lake levels in the Dead Sea basin have been robust recorders of the regional hydrology and generally indicate highstand (wet) conditions throughout glacial intervals and lowstands (dry) during interglacials. However, sporadic deposition of travertines and speleothems occurred in the Negev Desert and Arava Valley during past interglacials, suggesting intrusions of humidity from southern sources probably in association with enhanced activity of mid-latitude Red Sea synoptic troughs and/or low-latitude tropical plumes. The southerly incursions of wetness were superimposed on the long-term interglacial Levantine arid conditions, as reflected by the current prevailing hyperaridity, and could have had an important impact on human migra- tion through the Red Sea-Dead Sea corridor.

Puiggros, Adriana. Volver a educar. El desafío de la enseñanza argentina a finales del siglo XX. Buenos Aires, Ariel, 1995, 260 p.

Fil: Licata, Rosa. Universidad Nacional de Cuyo

Hugo Francisco Bauzá. Qué es un mito. Una aproximación a la mitología clásica. Buenos Aires, Fondo de Cultura Económica, 2005. 260 pp.

Fil: Sardi, Liliana.