Assortative mating for human height: A meta-analysis

OBJECTIVES: The study of assortative mating for height has a rich history in human biology. Although the positive correlation between the stature of spouses has often been noted in western populations, recent papers suggest that mating patterns for stature are not universal. The objective of this paper was to review the published evidence to examine the strength of and universality in assortative mating for height. METHODS: We conducted an extensive literature review and meta-analysis. We started with published reviews but also searched through secondary databases. Our search led to 154 correlations of height between partners. We classified the populations as western and non-western based on geography. These correlations were then analyzed via meta-analytic techniques. RESULTS: 148 of the correlations for partner heights were positive and the overall analysis indicates moderate positive assortative mating (r = .23). Although assortative mating was slightly stronger in countries that can be described as western compared to non-western, this difference was not statistically significant. We found no evidence for a change in assortative mating for height over time. There was substantial residual heterogeneity in effect sizes and this heterogeneity was most pronounced in western countries. CONCLUSIONS: Positive assortative mating for height exists in human populations, but is modest in magnitude suggesting that height is not a major factor in mate choice. Future research is necessary to understand the underlying causes of the large amount of heterogeneity observed in the degree of assortative mating across human populations, which may stem from a combination of methodological and ecological differences

Short CommunicationErythrocytic parameters as indicators for differentiating between the pregnant and pseudopregnant bitches in Nigeria

The erythrocytic parameters during pregnancy and pseudopregnancy in bitches were studied and compared in 8 bitches aged 2 -3 years and weighing 10–12 kg. Blood samples were collected from the bitches before mating, during the three trimesters of pregnancy and the post partum period. The packed cell volume (PCV %), haemoglobin concentration (Hb gm/dl), red blood cell count(x106/μl) were determined using standard methods. The mean corpuscular volume (MCV) and mean corpuscular haemoglobin concentration (MCHC) were then calculated. Six of the bitches were pregnant and 2 were pseudopregnant. The results showed that in pregnant bitches, the PCV decreased significantly from the premating values of 51.37+0.94% to 34.00 ± 8.04% during the third trimester of pregnancy (P<0.05). There was also a significant decrease in Hb values (P<0.05) from the premating period (16.30 ± 0.20gm/dl) to the third trimester of pregnancy (11.25 ± 1.80gm/dl). The values of Red blood cells (RBCx106/μl) during the premating period (12.70 ± 3.15) were not significantly different from the values during the first second and third trimesters (11.13 ± 3.87, 10.38 ± 4.54 and 12.24 ± 3.15, respectively). The trend of decrease in PCV and Hb values were not observed in the bitches with pseudopregnancy. This shows that these erythrocytic parameters can be used to detect and differentiate between pregnancy and pseudopregnancy in bitches as early as the first 20 days post mating. Keywords: Erythrocytic parameters, Pregnancy, Pseudopregnancy, Bitches. Nig. J. Physiol. Sci. 26(June 2011) 019 – 02

Effect of Formulation Methods on the Mechanical and Release Properties of Paracetamol Tablets

This work compared the compressional, mechanical and drug release properties of paracetamol tablets produced through direct compression with those obtained from wet granulation. Compressional properties were analyzed using density measurements, angle of repose, Carr’s index and Hausner’s ratio. The mechanical properties of the tablets were assessed using the crushing strength (CS), friability(F) and crushing strength-friability ratio (CSFR) of the tablets, while drug release properties were assessed using disintegration time and dissolution profile. The granules possessed better flow properties than the powder mixtures for direct compression. Paracetamol tablets prepared by wet granulation were harder than those prepared by direct compression as shown by the CS. The evaluation of the release properties showed that the amount of paracetamol released at any given time was higher for tablets prepared by direct compression than those prepared by wet granulation. Thus, wet granulation with carefully selected drug excipients may be a better method over direct compression in paracetamol tablets formulation.Keywords: Paracetamol tablets, direct compression, wet granulation, mechanical properties, drug release propertie