Applications of computerized stochastic models of human reproduction and population growth in family planning evaluation

This paper reports on the results of a computer experiment demonstrating some of the capabilities of computerized versions of a stochastic model of population growth [4] and a stochastic model of human reproduction [5] in family planning evaluation. The paper is divided into five sections, with Sec. 1 being devoted to a discussion of some of the motivations underlying the paper and the limitations of the results. Section 2 contains the numerical specifications of the component distributions of the model, and in Sec. 3 an experimental design is defined whereby the interactions of two alternative family building schemes, late versus early marriage, and low versus high desired family size may be studied with respect to population growth. The experimental design consists of eight reproductive regimes, and in Sec. 4 graphs of the calculated net maternity functions of these regimes together with the corresponding Malthusian parameter, the crude birth rate, and the mean number of female offspring in a completed family are presented. Section 5 is devoted to two population projections designed to measure the impact on population growth of two experimental schemes of transition from a high reproductive regime to a lower one. The indicators of population change and distributions used to measure the impact of these two experimental transitions in reproductive regimes as a function of time in these projections were crude birth rate, annual rate of population growth, age-specific birth rates, age distribution, and mean total population size.     

Some properties of the point processes generated by integral density modulation of renewal processes

Integral density modulation of point processes is defined, and the properties of the modulated point processes are described. When a homogeneous renewal process is modulated by a step random signal, the mathematical expressions are derived of the probability density functions of the sums of r-successive inter point intervals, the intensity functions and the first order correlation coefficient of intervals. These quantities are calculated and illustrated for several parameter values. Modulated point sequences are generated by computer simulation method. The interval histograms and the serial correlation coefficients of counts and of intervals of the sequences are obtained. The results are compared with the theoretical results on the point processes modulated by the step random signal.Abbreviations IDM Integral density modulation - SRS Step random signal - PP Point process - PS Point sequence - PDF Probability density function - CPDF Conditional probability density function - JCPDF Joint conditional probability density function - SED Special Earlangian distribution - SCC Serial correlation coefficients - SIC Serial intensity coefficients     

Nurse specialist in family planning.

In an experimental clinic, run by nurse specialists in family planning, a total of 768 patients were seen in the first year. Oral contraception was dispensed for 377 patients and 187 intrauterine devices (IUCDs) were inserted; a further 204 IUCD patients attended only for follow-up visits. All side effects were adequately diagnosed by the nurse specialist.     

Fertility and family planning in Accra

A sample of 1000 currently married women aged 25-39 and living in 3 geographic areas of the Ghanaian capital were interviewed about their contraceptive knowledge and practice. Slightly over 90% of the respondents said that they had heard of ways to delay or prevent pregnancy. There was no difference between the 3 areas, but more of those aged 30-34 had heard about contraception. The chances that a respondent had heard about contraception increased with the level of education. Catholics were less likely to have heard of any contraceptive methods than Protestants. Also, women engaged in traditional informal occupations were the least likely to have heard of any contraceptive methods. Overall, education emerged as the most important differentiating factor. The pill, condom, and IUD were the best known methods. Regarding actual contraceptive practice, only 41% of the respondents were currently using some form of contraception, with about 19% using modern and 27% traditional methods. Results of contraceptive usage by user characteristics show that the majority of women in 2/3 of the areas rely on a mixture of traditional and modern methods; that the % of users (any method) increases with age up to 30-34 years, after which it decreases. The % of ever-users of any type of contraception in this study is highest for the highest education levels, at 84% for women with 2ndary and post 2ndary education. With the exception of the IUD, douche and folklore methods, better educated women have higher ever-use %s for both traditional and modern methods. While the %s of users increases with education for foam, diaphragm and withdrawal; the reverse is observed for the pill and IUD, probably due to fear of negative side effects. Overall, there are no significant variations in contraceptive use by migration status; but the % of non-users is highest among recent migrants who are also the least likely to have ever used modern methods. Fertility differentials across ethnic groups have been observed in Ghana. The Akan have the highest fertility, followed by the Ewe and Ga-Adangbe with moderate fertility, and the northern ethnic groups with the lowest fertility. The Akan also have the highest % of ever users of modern contraceptives, an inconsistency which may be explained by their recent recognition of the burdens of high fertility and their attempts to control it. Religious differences are pronounced, especially between the traditional category on the 1 hand, and Christians and Muslims on the other. Results of an analysis of variance suggests that family size is the strongest motivation for adopting modern contraception, and that it may be used for limiting rather than spacing births.     

Men's approval of family planning in Bangladesh

This article attempts to evaluate men's approval of family planning in Bangladesh using the couple data set from the recent Bangladesh Demographic and Health Survey (BDHS), 1999-2000. Family planning approval is addressed both from individual and couple perspectives. Analysis of BDHS data shows that about 85% of the wives report that their husbands approve of family planning, which is lower than the wives' own approval rate (95%). Using the couple data set, husbands' characteristics were matched to the wives' responses on family planning approval. Regression analyses show that age, education, access to TV, inter-spousal communication, current use of family planning and the number of living children significantly determine family planning approval among both men as well as couples. Family planning approval was found to be much lower in Sylhet than in the other administrative divisions. Multilevel modelling analysis suggests almost negligible variation at the community level. The findings indicate the need for careful evaluation of the DHS questions in order to measure appropriately men's family planning attitudes.     

Desired family size, family planning and fertility in Ethiopia

This paper models the proximate determinants of children born to over 13,000 Ethiopian women and of the women's stated preferences for additional births using the data from the Ethiopian Demographic and Health Survey 2000. Empirical models for the number of children born to women were estimated using Poisson and ordinal regressions. The results show the importance of variables such as maternal education for smaller family size, and that variables reflecting desired family size are strong predictors of the numbers of children born to women. Secondly, binary logistic models for dichotomous variables for women not wanting more children and if getting pregnant would be a 'big problem' showed non-linear effects of the surviving and 'ideal' number of children. Moreover, the results indicated a desire on the part of women to limit family size, especially as the number of surviving children increased. Probit models were estimated to address potential endogeneity of certain variables. Overall, the results indicated that counselling couples about small family size and increasing the utilization of health care services can lower fertility in Ethiopia.     

Applications of yeast flocculation in biotechnological processes

A review on the main aspects associated with yeast flocculation and its application in biotechnological processes is presented. This subject is addressed following three main aspects—the basics of yeast flocculation, the development of “new” flocculating yeast strains and bioreactor development. In what concerns the basics of yeast flocculation, the state of the art on the most relevant aspects of mechanism, physiology and genetics of yeast flocculation is reported. The construction of flocculating yeast strains includes not only the recombinant constitutive flocculent brewer's yeast, but also recombinant flocculent yeast for lactose metabolisation and ethanol production. Furthermore, recent work on the heterologous β-galactosidase production using a recombinant flocculentSaccharomyces cerevisiae is considered. As bioreactors using flocculating yeast cells have particular properties, mainly associated with a high solid phase hold-up, a section dedicated to its operation is presented. Aspects such as bioreactor productivity and culture stability as well as bioreactor hydrodynamics and mass transfer properties of flocculating cell cultures are considered. Finally, the paper concludes describing some of the applications of high cell density flocculation bioreactors and discussing potential new uses of these systems.     

Making family planning accessible in resource-poor settings

It is imperative to make family planning more accessible in low resource settings. The poorest couples have the highest fertility, the lowest contraceptive use and the highest unmet need for contraception. It is also in the low resource settings where maternal and child mortality is the highest. Family planning can contribute to improvements in maternal and child health, especially in low resource settings where overall access to health services is limited. Four critical steps should be taken to increase access to family planning in resource-poor settings: (i) increase knowledge about the safety of family planning methods; (ii) ensure contraception is genuinely affordable to the poorest families; (iii) ensure supply of contraceptives by making family planning a permanent line item in healthcare system''s budgets and (iv) take immediate action to remove barriers hindering access to family planning methods. In Africa, there are more women with an unmet need for family planning than women currently using modern methods. Making family planning accessible in low resource settings will help decrease the existing inequities in achieving desired fertility at individual and country level. In addition, it could help slow population growth within a human rights framework. The United Nations Population Division projections for the year 2050 vary between a high of 10.6 and a low of 7.4 billion. Given that most of the growth is expected to come from today''s resource-poor settings, easy access to family planning could make a difference of billions in the world in 2050.     

An ethno-historic survey of family planning

Family planning in the Western sense -- where the motivation may be social, humanitarian, medical or economic and demographic -- does not exist among non-European populations. The various kinds of motivations for the limiting of the number of children among different and non-Western peoples are surveyed for 1 European group (the Saracatsans in Greece), Africa, Australia and the South Pacific, Asia, and South America. Children are regarded as a form of wealth and a retirement insurance for non-Western people, and contraceptive methods are sparingly used. In instances where contraceptives are used, there are different reasons for them; these are frequently related to a magico-religious belief and are of such means as decoctions of plant medicines. To a certain extent, these methods can have been effective at least psychologically. The practice of killing the newborn is often a product of the fear of misfortune striking the family should the child be permitted to live. The use of abortion has been a reasonably effective method, based on the dread of social pressure and eventually of punishment. Withdrawal is a generally widespread method. The introduction of tampons or other object into the vagina is found in several places.     

Obstacles to progress in family planning.

Two dip-tests, Testuria and Uricult, were studied as screening tests for bacteriuria in children. Both tests showed a very good correlation with a standard method of urine culture.Testuria is easier to read and more accurate; however, it shows more “doubtful” results. Uricult presents the advantages of showing fewer “doubtful” results, and of differentiating between gram-positive and gram-negative organisms.The use of both tests should be limited to screening for bacteriuria. Certainly they are no substitute for accepted methods of urine culture.