Fetal oxygen affinity and its parameters in a random obstetric population

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Book Reviews

Die hartJou Harl en Lewe. Deur A. J. Brink. Bl. 248. Gemustreer. RI6,95. Pretoria: Femina. 1982.The physiology of digestionExperiments and Observations on the Gastric Juice and the Physiology of Digestion. By William Beaumonr. 1st ed. 1&33. Reprinted in facsimile for the Classics ofMedicine Library, Division of Gryphon Editions Ltd, Birmingham, Alabama, 1980.Bone in Clinical Orthopaedics: A Study in ComparativeOsteology. Ed. by G. Sumner-Smith. Pp. xvi + 435. Illustrated. R94,25. Philadelphia: W. B. Saunders. 1982.Tamoxifen in breast cancerThe Role of Tamoxifen in Breast Cancer. Ed. by S. Iacobelli, M. E. Lippman and G. R. Della Cuna. Pp. xii + 124. Illustrated. 523,12. New York: Raven Press. 1982.Under the Influence. A History ofNitrous Oxide and OxygenAnaesthesia. By W. D. A. Smith. Pp. xxviii + 188. Illustrated. R33,50. London: Macmillan. 1982.Clinical internal medicine in the agedClinical Internal Medicine in the Aged. By R. W. Schrier. Pp. vii + 324. Illustrated. R61,-. Philadelphia: W. B. Saunders. 1982.Genital Infection by Chlamydia Trachomatis (Current Topicsin Infection, No. 2). By J. D. Oriel and G. L. Ridgway. Pp. viii + 144. Illustrated. R32,20. London: Edward Arnold. 1982.Placental Function Tests. By T. Chard and A. Klopper. Pp. viii + 94. Illustrated. DM42,-. Berlin: Springer-Verlag. 1982.Therapeutic Heat and Cold. 3rd ed. Ed. by J. F. Lehmann. Pp. xiv + 641. Illustrated. Baltimore: Williams & Wilkins. 1982

Budget Processes: Theory and Experimental Evidence

This paper studies budget processes, both theoretically and experimentally. We compare the outcomes of bottom-up and top-down budget processes. It is often presumed that a top-down budget process leads to a smaller overall budget than a bottom-up budget process. Ferejohn and Krehbiel (1987) showed theoretically that this need not be the case. We test experimentally the theoretical predictions of their work. The evidence from these experiments lends strong support to their theory, both at the aggregate and the individual subject level

Statistical mechanics of voting

Decision procedures aggregating the preferences of multiple agents can produce cycles and hence outcomes which have been described heuristically as `chaotic'. We make this description precise by constructing an explicit dynamical system from the agents' preferences and a voting rule. The dynamics form a one dimensional statistical mechanics model; this suggests the use of the topological entropy to quantify the complexity of the system. We formulate natural political/social questions about the expected complexity of a voting rule and degree of cohesion/diversity among agents in terms of random matrix models---ensembles of statistical mechanics models---and compute quantitative answers in some representative cases.Comment: 9 pages, plain TeX, 2 PostScript figures included with epsf.tex (ignore the under/overfull \vbox error messages

The Banks set and the Uncovered Set in budget allocation problems

We examine how a society chooses to divide a given budget among various regions, projects or individuals. In particular, we characterize the Banks set and the Uncovered Set in such problems. We show that the two sets can be proper subsets of the set of all alternatives, and at times are very pointed in their predictions. This contrasts with well-known "chaos theorems," which suggest that majority voting does not lead to any meaningful predictions when the policy space is multidimensional

Hydrothermal alteration of andesitic lava domes can lead to explosive volcanic behaviour

Dome-forming volcanoes are among the most hazardous volcanoes on Earth. Magmatic outgassing can be hindered if the permeability of a lava dome is reduced, promoting pore pressure augmentation and explosive behaviour. Laboratory data show that acid-sulphate alteration, common to volcanoes worldwide, can reduce the permeability on the sample lengthscale by up to four orders of magnitude and is the result of pore- and microfracture-filling mineral precipitation. Calculations using these data demonstrate that intense alteration can reduce the equivalent permeability of a dome by two orders of magnitude, which we show using numerical modelling to be sufficient to increase pore pressure. The fragmentation criterion shows that the predicted pore pressure increase is capable of fragmenting the majority of dome-forming materials, thus promoting explosive volcanism. It is crucial that hydrothermal alteration, which develops over months to years, is monitored at dome-forming volcanoes and is incorporated into real-time hazard assessments

Does the aldosterone: renin ratio predict the efficacy of spironolactone over bendroflumethiazide in hypertension? A clinical trial protocol for RENALDO (RENin-ALDOsterone) study

<p>Background: High blood pressure is an important determinant of cardiovascular disease risk. Treated hypertensives do not attain a risk level equivalent to normotensives. This may be a consequence of suboptimal blood pressure control to which indiscriminate use of antihypertensive drugs may contribute. Indeed the recent ALLHAT[1]study suggests that thiazides should be given first to virtually all hypertensives. Whether this is correct or whether different antihypertensive therapies should be targeted towards different patients is a major unresolved issue, which we address in this study.</p> <p>The measurement of the ratio of aldosterone: renin is used to identify hypertensive subjects who may respond well to treatment with the aldosterone antagonist spironolactone. It is not known if subjects with a high ratio have aldosteronism or aldosterone-sensitive hypertension is debated but it is important to know whether spironolactone is superior to other diuretics such as bendroflumethiazide in this setting.</p> <p>Methods/design: The study is a double-blind, randomised, crossover, controlled trial that will randomise 120 hypertensive subjects to 12 weeks treatment with spironolactone 50 mg once daily and 12 weeks treatment with bendroflumethiazide 2.5 mg once daily. The 2 treatment periods are separated by a 2-week washout period. Randomisation is stratified by aldosterone: renin ratio to include equal numbers of subjects with high and low aldosterone: renin ratios.</p> <p>Primary Objective – To test the hypothesis that the aldosterone: renin ratio predicts the antihypertensive response to spironolactone, specifically that the effect of spironolactone 50 mg is greater than that of bendroflumethiazide 2.5 mg in hypertensive subjects with high aldosterone: renin ratios.</p> <p>Secondary Objectives – To determine whether bendroflumethiazide induces adverse metabolic abnormalities, especially in subjects with high aldosterone: renin ratios and if baseline renin measurement predicts the antihypertensive response to spironolactone and/or bendrofluazide.</p> <p>Discussion: The numerous deleterious effects of hypertension dictate the need for a systematic approach for its treatment. In spite of various therapies, resistant hypertension is widely prevalent. Among various factors, primary aldosteronism is an important cause of resistant hypertension and is now more commonly recognised. More significantly, hypertensives with primary aldosteronism are also exposed to various other deleterious effects of excess aldosterone. Hence treating hypertension with specific aldosterone antagonists may be a better approach in this group of patients. It may lead on to better blood pressures with fewer medications.</p&gt