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Plants, animals and microorganisms are being manipulated to improve their characteristics for commercial purposes. Some manipulated organisms will be grown under containment and only released to the environment accidentally and, usually, in relatively small numbers. Others, such as crop plants, will be grown on a large scale in the open environment. There is concern that modified organisms may become pests, or will produce pests as a result of mating with other organisms in the environment.
This paper will discuss some of the issues involved in deciding whether genetically modified plants should be released to the environment or not.
Thyroid hormones are important in the development of the fetus and the placenta as well as in maintaining maternal wellbeing. Thyroid disorders are common in the population as a whole, particularly in women, and therefore are common during pregnancy and the puerperium. Biochemical derangement of thyroid function tests are present in approximately 2.5–5% of pregnant women.
Skin carriage of Acinetobacter calcoaceticus-baumannii complex was not detected among a representative sample of 102 US Army soldiers stationed in Iraq. This observation refutes the hypothesis that preinjury skin carriage serves as the reservoir for the Acinetobacter infections seen in US military combat casualties.
Operational sex ratio (OSR) is the correct sex ratio measure for predicting sociosexuality, but it is unclear whether this is the measure used. It would be valuable to know how OSR and sociosexuality correlate separately for males and females. The relationship between sociosexuality and OSR should also be examined with OSR measured at the local level of the mating market, where sex ratio must be having its psychological effects.
The importance of understanding human cooperation urges further integration between the relevant disciplines. I suggest ideas for bottom-up and top-down integration. Evolutionary psychology can investigate the kinds of reasoning it was adaptive for humans to employ. Disciplines can learn from each other's approaches to similar problems, and I give an example for economics and evolutionary biology.
This chapter considers the factors influencing population birth sex ratios and variations of the sex ratio within populations, together with adaptive interpretations of these effects and the mechanisms underlying them. Adaptations and mechanisms for birth sex ratios are poorly understood, whereas variation in the sexual biasing of postnatal investment is more clearly adaptive. Social and demographic factors influencing birth sex ratios and postnatal investment include: parental status (the Trivers-Willard effect), father's age, birth order and local resource enhancement and competition. Complex effects are expected since many causal factors may interact at different times during offspring dependency. Possible mechanisms for control of the birth sex ratio include: the proportion of X and Y sperm in ejaculates; the relative success of X and Y sperm in fertilization, as determined by hormonal changes over the menstrual cycle interacting with the time of insemination and coital frequency; and embryonic mortality. Prospects for new work emerge from the following analyses: mechanisms for the Trivers-Willard effect (X and Y sperm proportions in ejaculates, coital frequency, embryonic mortality, family size and paternal age; predicting adaptation from proposed mechanisms and ancestral states; relationships between status, reproductive success and its variance; measuring status more realistically; and marginal return as the correct measure for predicting investment.
The peculiar fascination with the human sex ratio at birth has a number of sources.
Women who are positive for thyroid antibodies in early gestation are prone to post-partum depression, apparently independent of thyroid dysfunction, as measured by serum levels of free thyroxine, free triodothyroxine and thyroid-stimulating hormone. This finding may be due to infrequent monitoring of thyroid function, because hyperthyroidism, hypothyroidism and combinations of both may occur post-partum.
To test the hypothesis that stabilising thyroid function post-partum by administering daily thyroxine reduces the rate of occurrence and severity of associated depression.
In a randomised double-blind placebo-controlled trial, 100 of thyroxine or placebo was given daily to 446 thyroid-antibody-positive women (342 of whom were compliant) from 6 weeks to 6 month spost-partum, assessing their psychiatric and thyroid status at 4-weeklyintervals.
There was no evidence that thyroxine had any effect on the occurrence of depression. The 6-month period prevalence of depression was similar to that reported previously.
The excess of depression in thyroid-antibody-positive women in the post-partum period is not corrected by daily administration of thyroxine.
Seventy-three patients who had been continuously receiving lithium carbonate for 6 months or more had their thyroid function evaluated clinically and biochemically. Goitre was found in 37 %, exophthalmos in 23 %, positive thyroid auto-antibodies in 24 % and abnormal TRH tests in 49 %. It would appear that thyroid failure due to lithium is usually dependent on antibody mediated damage. It is unlikely that lithium has a direct effect on the hypothalamic–pituitary axis.
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