3,613 research outputs found
Hodge filtered complex bordism
We construct Hodge filtered cohomology groups for complex manifolds that
combine the topological information of generalized cohomology theories with
geometric data of Hodge filtered holomorphic forms. This theory provides a
natural generalization of Deligne cohomology. For smooth complex algebraic
varieties, we show that the theory satisfies a projective bundle formula and
\A^1-homotopy invariance. Moreover, we obtain transfer maps along projective
morphisms.Comment: minor revision; final version accepted for publication by the Journal
of Topolog
The Chemical State of the Calcium Reacting in the Coagulation of Blood
1. The widely accepted theory that calcium participates in the coagulation mechanism in the form of Ca++ and acts as a catalyst is not in accord with several important experimental findings:
(a) The anticoagulant action of sodium oxalate is much slower than the precipitation of ionized calcium as the oxalate salt.
(b) Sodium citrate begins to depress prothrombin activity at a concentration at which ionized calcium is still present. The inability of tricalcium phosphate to adsorb prothrombin from citrated plasma indicates that citrate forms a complex with prothrombin and it is postulated that prothrombin is thereby inactivated.
(c) In plasma which is decalcified, i.e. in which the Ca++ is markedly reduced, the labile factor of prothrombin rapidly decreases. A concentration of 0.01 M sodium citrate sufficient to inhibit coagulation does not depress Ca++ enough to cause diminution of the labile factor, whereas when the concentration is increased to 0.02 M the labile factor decreases as rapidly as in oxalated plasma.
2. It is postulated that calcium functions in coagulation not as Ca++ but as combined with a component which is part of the prothrombin complex that is not adsorbed by tricalcium phosphate. A concentration of sodium citrate just sufficient to inhibit coagulation is not enough to remove calcium from the essential prothrombin component. The primary anticoagulant action of sodium citrate is therefore not decalcification but antiprothrombic.
3. It has been shown that citrated plasma is basically different from oxalated plasma in several important aspects. Unless cognizance is taken of these differences, serious errors and misinterpretations of experimental findings may be made
The role of tectonic inheritance, plate-reorganization, and magma flare-ups in the evolution of the Sevier Orogeny
The temporal and spatial distribution of strain associated with the Sevier Orogeny in western North America is significantly different in the southern end of the belt, at the latitude of Las Vegas, than further to the north at the latitude of Salt Lake City. Until this study, reasons for these differences were speculative as a lack of thrust kinematic data in the intervening region hindered along strike correlation across the belt. A crystallization age of 100.18 ± 14 0.04 Ma was determined for zircons extracted from a recently recognized ash fall tuff near the base of the synorogenic Iron Springs Formation at Three Peaks, Iron County, Utah. Field relationships and this age constrain movement on the Iron Springs thrust and the end of the sub-Cretaceous unconformity in the critical intervening area to latest Albian/earliest Cenomanian. Movement on the Iron Springs thrust and other Sevier thrusts at ~100 Ma is synchronous with a period of global plate reorganization and a high convergence rate for the Farallon Plate, which led to a Cordilleran arc flare-up event, and triggered widespread thrusting across the retroarc Sevier deformation belts. Based on these results, we suggest temporal and spatial variation along the strike of the orogenic belt are inherited from variation in the thickness of the rifted Precambrian craton --Abstract, page iv
Stimulation of erythropoietin in renal insufficiency by hypobaric hypoxia
Patients with renal anaemia show inadequate levels of immunoreactive erythropoietin (Epo) related to the degree of anaemia. The purpose of our study is to compare the degree of stimulation of Epo by means of hypobaric hypoxia in normal controls and patients with renal anaemia. Baseline Epo concentrations were found to be 11.1±2.0 U/l in 10 healthy volunteers and 11.4±4.6 U/l in six patients with renal anaemia. After exposure to hypobaric hypoxia equivalent to 4560 m above sea level for a duration of 3.5 h, we observed a significant increase in serum Epo in healthy volunteers to 22.8±9.1 U/l (P<0.005), while there was no increase in patients with renal anaemia: 12.3±5.2 U/l (P<0.2). Our results show that in patients with renal anaemia serum Epo concentrations are comparable to those of normal controls, but inadequate in view of the concomitant degree of anaemia. Stimulation by acute hypobaric hypoxia was not possible in patients with renal insufficiency as opposed to normal controls. From these data it can be concluded that either Epo production is working at maximum capacity under baseline conditions, or an additional hybobaric stimulus is not able to influence a disturbed set point of the oxygen sensor regulating Epo synthesi
VIC ... High Yielding, Strong Gluten Durum
'Vic' (CI 17789) is a durum wheat cultivar (variety) developed by the North Dakota Agricultural Experiment Station, North Dakota State University, in cooperation with Agricultural Research, Science and Education Administration, the U. S. Department of Agriculture. Vic combines high grain yield and strong gluten characteristics. Gluten strength gives superior cooked firmness to various pasta products made from durum semolina. The improved yielding ability and strong gluten of Vic should make it a potential replacement for all presently grown normal height cultivars. Vic was developed in only six years from the final cross by utilizing early generation (F 3) yield and quality testing and three years of winter nurseries
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