Experimental analysis of eleven models of urban population density

Seven models of the quadratic gamma type (negative-exponential, normal, inverse-power, quadratic negative-exponential, gamma, normal gamma, and quadratic gamma distributions) and the equilibrium models of Amson are tested by use of data from Bristol, Coventry, Derby, Leicester, Nottingham, Leeds, and Bradford. The first five of these cities are tested at two levels: By use of all radial distances and by use of only those less than four kilometres. The object of these tests was to detect differences in goodness of fit at the city centre and overall. The last two cities were used to test a model proposed to describe intercity population distributions.

Is measurement of placental function and maternal weight worth while?

A prospective survey of 1029 women delivered during 1976 at St. Bartholomew's Hospital was undertaken to assess the predictive value of a variety of clinical, ultrasonic, and biochemical variables in the detection of high-risk pregnancies. The best antenatal predictors of fetal risk were severe pre-eclampsia, depressed maternal serum levels of human placental lactogen, low maternal weight at 32 weeks' gestation, and heavy smoking by the mother. 62% of the high-fetal risk group had one or more of these features, but so did 33% of the controls.

Incidence of depressive symptoms in users of the oral contraceptive

Evidence is presented that the incidence of depression among users of oral contraceptives is no higher than that among matched controls not taking such medication. There is an association between high depression scores and high neuroticism scores, more marked in controls than takers. Intensity of depression is related more to age, personality and occupation than to the use of oral contraceptives. A higher proportion of users than of controls experience sexual satisfaction. Past takers include a large number of individuals with a high neuroticism score. The incidence of depression symptoms in women increases with age. A higher proportion of housewives than of women going out to full-time work show depressive symptoms.

Changes in peripheral hormone levels after therapeutic abortion

Plasma levels of progesterone, 17 alpha-OH progesterone, hPL and beta-subunit hCG were measured in a group of women for 24 h after therapeutic abortion. Progesterone, hCG and hPL levels fell more rapidly than 17 alpha-OH progesterone levels. This might suggest that the main site of synthesis of 17 alpha-OH progesterone is probably in the corpus luteum of pregnancy or that the prolonged half-life of hCG maintains the corpus luteum to secrete longer. Human placental lactogen fell dramatically within 4 h but the hCG level was maintained. This difference probably reflects only the differences in half-lives of these hormones.

Spontaneous abortion, sex ratio and facial cleft malformations

In family and reproductive data combined from five treatment centers, relating to 861 index cases with cleft lip (with or without cleft palate, CL+/-P), maternally recognized spontaneous abortions were found to be significantly less frequent in sibships including two or more cases of CL+/-P than in sibships including only one case. In data relating to 379 index cases with cleft palate (CP), maternally recognized spontaneous abortions were reduced to a degree short of formal significant in sibships including two or more cases of CP by comparison with sibships including only one case of CP. The sex ratio among the sibs of parents of CL+/-P index cases was elevated when the index case was the only affected child and reduced when the index case had one or more affected sibs. Considered in combination with the results of other investigations, these findings indicate the existence of inherited factors reducing abortion frequency in the sibships of CL+/-P index cases. These factors appear to be unrelated to those for liability to CL+/-P.

Changes in the size distribution of settlements in England and Wales, 1801-1968

Changes over time in the distribution of settlement sizes in England and Wales are examined by using two data sets: Town population sizes 1801–1911 and the population size of various local government units in 1968. The Cohen and Whitworth random partitioning models are applied to these data. Standard normal deviates show the increasing population concentration in large urban areas during the 19th century and the reversal of this trend in the 20th century, leading to the suggestion of maximum entropy in 1968. A comparison of the Cohen and the rank–size models suggests the greater utility of the former once the primate city is excluded from consideration. The analysis highlights the timing of critical changes in the evolution of the settlement pattern, particularly the reversal of trend in 1901.