Malaria ecology, child mortality & fertility.

The broad determinants of fertility are thought to be reasonably well identified by demographers, though the detailed quantitative drivers of fertility levels and changes are less well understood. This paper uses a novel ecological index of malaria transmission to study the effect of child mortality on fertility. We find that temporal variation in the ecology of the disease is well-correlated to mortality, and pernicious malaria conditions lead to higher fertility rates. We then argue that most of this effect occurs through child mortality, and estimate the effect of child mortality changes on fertility. Our findings add to the literature on disease and fertility, and contribute to the suggestive evidence that child mortality reductions have a causal effect on fertility changes

Do Business Cycles Make Babies? The Effect of Business Cycle Fluctuations On Fertility

Economic models often treat fertility as both constant and exogenous, while neither assumption is true. In this paper, I develop a Real Business Cycle model to analyze the impact of business cycle fluctuations on household fertility decisions. I incorporate a fertility decision into a search-based labor market and conduct a general equilibrium analysis of the effects of business cycles. The simulated results show that households increase their fertility during positive economic times, and reduce fertility as unemployment rises

Why we measure period fertility

Four reasons for measuring period fertility are distinguished: to explain fertility time trends, to anticipate future fertility, to construct theoretical models and to communicate with non-specialist audiences. The paper argues that not all measures are suitable for each purpose, and that tempo adjustment may be appropriate for some objectives but not others. In particular, it is argued that genuine timing effects do not bias or distort measures of period fertility as dependent variable. Several different concepts of bias or distortion are identified in relation to period fertility measures. Synthetic cohort indicators are a source of confusion since they conflate measurement and forecasting. Anticipating future fertility is more akin to forecasting than to measurement. Greater clarity about concepts and measures in the fertility arena could be achieved by a stronger emphasis on validation. Period incidence and occurrence-exposure rates have a straightforward interpretation. More complex period fertility measures are meaningful only if a direct or indirect criterion can be specified against which to evaluate them. Their performance against that criterion is what establishes them as valid or useful

Latest‐Late Fertility? Decline and Resurgence of Late Parenthood Across the Low‐Fertility Countries

After decades of fertility postponement, we investigate recent changes in late parenthood across low-fertility countries in the light of observations from the past. We use long series of age-specific fertility rates from the Human Fertility Database (1950– 2016) for women, and new data covering the period 1990–2016 for men. In 1950, the contribution of births at age 40 and over to female fertility rates ranged from 2.5 to 9 percent, but then fell sharply until the 1980s. From the 1990s, however, the prevalence of late first births increased rapidly, especially so in countries where it was initially lowest. This has produced a late fertility rebound in the last two decades, occurring much faster for women than for men. Comparisons between recent and past extremely late (age 48+) fertility levels confirm that people are now challenging the natural fertility barriers, particularly for a first child

Protocol for Determining Fertility While Breastfeeding and Not in Cycles

A protocol was developed and evaluated for nonovulating breastfeeding women to determine potential fertility with an electronic hormonal fertility monitor. The amount of required abstinence (i.e., days of potential fertility) through the first menstrual cycle indicated by the fertility monitor was significantly lower (17% of the total days) compared with the amount of abstinence (50% of the total days) indicated by the self-observation of cervical mucus

A diminishing population whose every cohort more than replaces itself

We observe that a dynamic population model can have period fertility that is always below replacement and cohort fertility that is always above replacement. We ask whether such a paradoxical population will get larger or smaller, and show that it must become smaller. Cohort replacement does not imply population replacement, and emphasizing fertility timing and cohort fertility ignores the issue of relative cohort size. The resolution of this apparent paradox reinforces the importance of the level of period fertility in demographic analysis.Bongaarts-Feeney adjusted fertility, cohort, cohort fertility, dynamic population model, fertility, fertility timing, period fertility

Effect of organic, low-input and conventional production systems on yield and diseases in winter barley

The effect of organic, low-input and conventional management practices on barley yield and disease incidence was assessed in field trials over two years. Conventional fertility management (based on mineral fertiliser applications) and conventional crop protection (based on chemosynthetic pesticides) significantly increased the yield of winter barley as compared to organic fertility and crop protection regimes. Severity of leaf blotch (Rhynchosporium secalis) was highest under organic fertility and crop protection management and was correlated inversely with yield. For mildew (Erysiphe graminis), an interaction between fertility management and crop protection was detected. Conventional crop protection reduced severity of the disease, only under conventional fertility management. Under organic fertility management, incidence of mildew was low and application of synthetic pesticides in “low input” production systems had no significant effect on disease severity

Is low fertility really a problem? Population aging, dependency, and consumption.

Copyright 2014 by the American Association for the Advancement of Science; all rights reserved.Longer lives and fertility far below the replacement level of 2.1 births per woman are leading to rapid population aging in many countries. Many observers are concerned that aging will adversely affect public finances and standards of living. Analysis of newly available National Transfer Accounts data for 40 countries shows that fertility well above replacement would typically be most beneficial for government budgets. However, fertility near replacement would be most beneficial for standards of living when the analysis includes the effects of age structure on families as well as governments. And fertility below replacement would maximize per capita consumption when the cost of providing capital for a growing labor force is taken into account. Although low fertility will indeed challenge government programs and very low fertility undermines living standards, we find that moderately low fertility and population decline favor the broader material standard of living