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

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

Perfect design or practical study? A workshop on navigating the challenges of community based prevention research

Subject: There is a shared interest among public health researchers in tackling methodological issues surrounding community based research, and on moving beyond a focus on individual level change. As part of a project on community empowerment funded by the People’s Health Trust, we have conducted a feasibility study on quantitative and economic evaluation of complex community-based interventions. To understand different quantitative methods that can be used to evaluate community empowerment interventions, we have undertaken a methodological literature review that identified the following sets of challenges: Defining population of interest – interventions taking place at a community level are not specifically targeted at a well-defined group of individuals. Therefore it is challenging to even find those who are affected by an intervention. Diverse and un-prescribed effects – the effect of community empowerment interventions are likely broad, suggesting we need to measure multiple outcomes in order to detect change. This increases the likelihood of detecting spurious change and can require a lot of resource. Furthermore, in many cases these outcomes are not pre-defined by a programme (i.e. communities choose their own foci)