Associations of body mass index and waist:hip ratio with hypertension.

Canada Fitness Survey data for people aged 20 to 69 years were analysed by means of linear discriminant analysis to determine the effect of age, weight relative to height (body mass index) and weight distribution (waist:hip ratio) on hypertension (defined as diastolic blood pressure of 90 mm Hg or more) for both sexes separately. All three variables had independent effects on hypertension, but partial correlation coefficients indicated that the contribution of waist:hip ratio was secondary to that of body mass index. The association of measurements of body fat (five skinfold measurements) with hypertension was also examined; overall these measurements gave no advantage over the more simply measured body mass index. The results confirm the importance of assessing the predominant location of body fat and the body mass index when examining excess weight in relation to disease.     

Changes in otolith area: sensory area ratio with body size and depth

Synopsis The ratio between the sensory areas of the sulcus acusticus and the sagittal otolith (S : O ratio) in the species Merluccius capensis and M. paradoxus was analyzed using a digital image processing system. Sagittal growth in both species is negatively allometric with respect to total fish length but is more negative in the deeper-dwelling species, Merluccius paradoxus. In contrast, the sulcus acusticus undergoes a relative increase in size, that is, the S : O ratio increases with fish length. There was a clear relationship between the increase in the S : 0 ratio and depth.     

An experimental study of body size and food size relations in crucian carp,Carassius carassius

Synopsis In dense, single-species assemblages of crucian carp, competition is intense and results in populations of stunted fish. To explore mechanisms underlying this competition, we measured handling times, return rates, and prey choice for five sizes of crucian carp feeding on six sizes of a standardized food. Handling times increased with prey size and decreased with fish size. Return rates (dry mass ingested per unit handling time) increased dramatically with fish size, and generally decreased with increasing prey size, especially for small fish. Patterns of return rates among size-classes suggested that one or more size-related shifts in feeding efficiency exist for crucian carp; combined with physiological stresses related to winter anoxia, the inability of fish to make these shifts may contribute to size structures observed in high-density populations. Comparisons of relations among fish size, prey size, and return rates for crucian carp and bluegill, Lepomis macrochirus, suggest that similar intraspecific competitive relations exist between generalist species with size-structured populations. Despite differences in return rates among prey sizes, the extent of food selectivity based on prey size exhibited by crucian carp in two types of choice trials was less than predicted. Crucian carp commonly take in several items before mechanically processing food with their pharyngeal apparatus; this multiple prey processing may contribute to disparities between observed choice patterns and those predicted based on return rates for single prey.     

Male preferences for female waist‐to‐hip ratio and body mass index in the highlands of Papua New Guinea

One hundred men, living in three villages in a remote region of the Eastern Highlands of Papua New Guinea were asked to judge the attractiveness of photographs of women who had undergone micrograft surgery to reduce their waist‐to‐hip ratios (WHRs). Micrograft surgery involves harvesting adipose tissue from the waist and reshaping the buttocks to produce a low WHR and an “hourglass” female figure. Men consistently chose postoperative photographs as being more attractive than preoperative photographs of the same women. Some women gained, and some lost weight, postoperatively, with resultant changes in body mass index (BMI). However, changes in BMI were not related to men's judgments of attractiveness. These results show that the hourglass female figure is rated as attractive by men living in a remote, indigenous community, and that when controlling for BMI, WHR plays a crucial role in their attractiveness judgments. Am J Phys Anthropol, 2010. © 2009 Wiley‐Liss, Inc.     

Association of birth weight and current body size to blood pressure in female twins.

It has been proposed that low birth weight is associated with high levels of blood pressure in later life. The aim of this study was to assess the relationship of blood pressure to birth weight and current body size during growth and adulthood. A total of 711 female multiple births, with one group of 244 in their growth phase mean age 12.0 (2.3)(SD) years and the other of 467 adults (mean age 35.2 (12.6) years), had height, weight and both systolic (SBP) and diastolic (DBP) blood pressures measured, and self-reported their birth weight. Regression analyses were performed to assess the cross-sectional and within-pair associations of blood pressure to birth weight, with and without adjustments for current body size. Within-pair analysis was based on 296 twin pairs. Cross-sectionally, a reduction in birth weight of 1 kg was associated with 2 to 3 mm Hg higher age-adjusted SBP, which was of marginal significance and explained about 2% of the population variance. Adjustment for body mass index did not significantly change this association. Within-pair analyses found no association between birth weight and SBP or DBP,even after adjusting for current body size. After age, current body size was the strongest predictor of systolic BP. The weak association of blood pressure to birth weight cross-sectionally is of interest, but any within-pair effect of birth weight on blood pressure must be minimal compared with the effect of current body size.     

A comparative study of body size and clutch size across the parasitoid Hymenoptera

Across animal species, body size and clutch size often form part of a suite of associated life history traits, exemplified by the "fast-slow continuum" in mammals. Across the parasitoid Hymenoptera however, a major axis of life history variation is the development mode of the larva (koinobiosis versus idiobiosis), and body size and clutch size do not seem to form clear associations with this major axis. Here we use a large comparative data set and the latest phylogenetic information to explore hypotheses that might explain the variation in body size and clutch size across species in parasitoids. We find evidence for three novel evolutionary correlations: changes in the stage of host attacked by the parasitoid (i.e. egg, larva, pupa) significantly predict changes in both body size and clutch size, whilst in gregarious species changes to higher latitudes are associated with reduced clutch size. We also find a number of hypothesized cross-species (phenotypic) associations that, however, we cannot demonstrate are the result of evolutionary correlations: large bodied species in our data tend to lay small clutches; koinobionts are larger than idiobionts attacking the same host stage; tropical species are smaller than temperate species (Bergmann's rule). Our results provide support for theoretical models of trait evolution in parasitoids, whilst the associations between latitude and life history may help explain why species richness in the family Ichneumonidae peaks at intermediate latitudes. Our results also show the continuing value of phylogenetically-based comparative analyses and demonstrate that recent work on parasitoid phylogenetics has produced significant benefits for our understanding of life history evolution.     

Fecundity and egg viability in relation to female body size in Neodiprion sertifer (Hymenoptera: Diprionidae)

Relationships between female size and fecundity, egg viability and embryonal development were studied in Neoriprion sertifer. Sawfly females, reared from the 1st instar larvae on Scots pine needles heavily affected by industrial pollutants or on relatively unpolluted needles, were induced to lay eggs parthenogenetically in the field in Finland. Females reared on polluted needles were smaller and oviposited an average of 68.8 eggs, and those reared on unpolluted needles 79.4 eggs per female. However, the higher egg viability in the former group masked the effect of reduced female size. This compensation was primarily related to the size of the females, larger individuals producing relatively fewer viable eggs in both groups.     

An electron microscopic study of Borrelia in the body of the female ixodid tick Ixodes persulcatus

Borrelia burgdorferi s. lato in naturally infected females of tick Ixodes persulcatus were examined by transmission electron microscopy. The Borreliae were found in midgut and ovary. Location and ultrastructure of bacteria indicate extracellular migration through the midgut epithelium as a preferential way. In gonad, the borreliae intracellular situate in ovarian epithelium and oocytes before and at the beginning of vitellogenesis. The demonstration of numerous spirochetes in the oocytes provides the support for transovarial transmission of the agent. Two morphological types of borreliae were observed.     

Genomics and transcriptomics to study fruiting body development: An update

Fruiting bodies of asco- and basidiomycetes are complex three-dimensional structures that protect and disperse the sexual spores. Their differentiation requires the concerted action of many genes, therefore "omics" techniques to analyze fungal genomes and gene expression at a genome-wide level provide excellent means to gain insights into this differentiation process. This review summarizes some recent examples of the use of “omics” techniques to study fruiting body morphogenesis. These include genome-centered analyses, and studies to analyze the regulation of gene expression including the analysis of RNA editing as a novel layer in the regulation of gene expression during fruiting body development in ascomycetes.     

Patterns of eye movements when male and female observers judge female attractiveness, body fat and waist-to-hip ratio

Behavioural studies of the perceptual cues for female physical attractiveness have suggested two potentially important features: body fat distribution [the waist-to-hip ratio (WHR)] and overall body fat [often estimated by the body mass index (BMI)]. However, none of these studies tell us directly which regions of the stimulus images inform observers' judgments. Therefore, we recorded the eye movements of three groups of 10 male observers and three groups of 10 female observers, when they rated a set of 46 photographs of female bodies. The first sets of observers rated the images for attractiveness, the second sets rated for body fat and the third sets for WHR. If either WHR and/or body fat is used to judge attractiveness, then observers rating attractiveness should look at those areas of the body which allow assessment of these features, and they should look in the same areas when they are directly asked to estimate WHR and body fat. So we are able to compare the fixation patterns for the explicit judgments with those for attractiveness judgments and infer which features were used for attractiveness. Prior to group analysis of the eye-movement data, the locations of individual eye fixations were transformed into a common reference space to permit comparisons of fixation density at high resolution across all stimuli. This manipulation allowed us to use spatial statistical analysis techniques to show the following: (1) Observers' fixations for attractiveness and body fat clustered in the central and upper abdomen and chest, but not the pelvic or hip areas, consistent with the finding that WHR had little influence over attractiveness judgments. (2) The pattern of fixations for attractiveness ratings was very similar to the fixation patterns for body fat judgments. (3) The fixations for WHR ratings were significantly different from those for attractiveness and body fat.     

Mixing and matching in ceramic-on-metal hip arthroplasty: An in-vitro hip simulator study

The clinical success of second-generation metal-on-metal hip replacement and the good tribological performance of alumina ceramic revived an interest in hip articulation as a solution to reduce wear.This study was aimed at characterizing the wear behaviour of new hybrid ceramic-on-metal bearings. In particular, this study investigated the wear behaviour of ceramic-on-metal hip components (three different diameters configurations: 28, 32 and 36 mm), not specifically proposed to be coupled, in order to compare them with ceramic-on-ceramic, which is considered to be the gold standard for wear resistance. For this purpose, the weight loss over a standard wear simulation was monitored. Moreover, scanning electronic microscope observations were used to verify if any carbides removal, for the metallic components, triggered wears debris production promoting abrasive third-body wear.After five million cycles, our results showed significantly greater wear-in ceramic-on-metal compared with ceramic-on-ceramic, and significant greater wear for the 32-mm diameter compared with the 36-mm one. Our findings showed an increase in wear for the proposed hybrid specimens with respect to that of the ceramic-on-ceramic ones confirming that even in the case of ceramic-on-metal bearings, mixing and matching could not prove effective wear behaviour, not even comparable with that of the ceramic-on-ceramic gold standard. Wear patterns and roundness tolerances certainly discourage the coupling of components not specifically intended to be coupled. Unsuitable geometrical conformity could, in fact, result in a poor dynamic behaviour and lead to clinical failure.     

The influence of female age and host size on the sex ratio of the parasitoid Opius concolor

The sex ratio of the progeny of single females parasitizing large hosts favoured the females (sex ratio=0.26); but on small hosts favoured the males (0.73). No differences in mortality of the sexes were detected. The sex ratio was independent of female age when large hosts were used. The percentage of males observed in the progeny of the first day of female oviposition was significantly greater than the mean, irrespective of the age at which female oviposition began. When females were exposed to small hosts, a greater percentage of females was observed in the progeny from the last days of oviposition.

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Résumé L'influence de la taille de l'hôteret de l'âge de la femelle sur le taux sexuel de la descendance a été étudiée sur le parasitoïde Opius concolor Szépl.Le taux sexuel de la descendance des femelles isolées est favorable aux femelles (t.s.=0,26) quand elles ont à leur disposition des hôtes de grande taille, tandis qu'avec des hôtes petits le taux sexuel est favorable aux mâles (t.s.=0.73). On n'a pas détecté de mortalité différentielle des sexes.Les pourcentage de mâles obtenu le premier jour de ponte des femelles sur les hôtes de grande taille est significativement différent de la moyenne, indépendamment de l'âge de la femelle à ce moment. Cependant, sur des hôtes petits, bien que restant favorable aux mâles dans l'ensemble, une plus grande proportion de femelles à partir des premiers jours de ponte a pu être observée.

     

Offspring sex ratio is related to male body size in the great tit (Parus major)

Sex allocation theory predicts that the allocation of resourcesto male and female function should depend on potential fitnessgain realized through investment in either sex. In the greattit (Parus major), a monogamous passerine bird, male resourceholdingpotential (RHP) and fertilization success both depend on malebody size (e.g., tarsus length) and plumage traits (e.g., breaststripe size). It is predicted that the proportion of sons ina brood should increase both with male body size and plumage traits,assuming that these traits show a father—offspring correlation. Thiswas confirmed in our study: the proportion of sons in the brood increasedsignificantly with male tarsus length and also, though not significantly,with the size of the breast stripe. A sex ratio bias in relationto male tarsus length was already present in the eggs because(1) the bias was similar among broods with and without mortalitybefore the nestlings' sex was determined, and (2) the bias remainedsignificant when the proportion of sons in the clutch was conservativelyestimated, assuming that differential mortality before sex determinationcaused the bias. The bias was still present among recruits.The assumption of a father—offspring correlation was confirmedfor tarsus length. Given that both RHP and fertilization successof male great tits depend on body size, and size of father andoffspring is correlated, the sex ratio bias may be adaptive.     

The ontogeny of the neurophysiological mechanisms of stereognosis: An EEG study

Age-related characteristics of the systemic organization of intra- and interhemispheric interactions during a stereognostic task (tactile shape recognition with the right or left hand) were studied in adults and children aged five to six, seven to eight, and nine to ten years. A combined pattern of cortical interactions was found in adults. It was expressed in a considerable enhancement of relationships between cortical bioelectric potentials compared to the baseline accompanied by a substantial increase in the intensity of the systemic interactions between anterior and posterior cortical areas. This pattern was revealed by both coherence and cross-correlation analyses of the electroencephalogram (EEG). In the EEGs of children, the enhancement of interhemispheric relationships was observed at an age as early as five to six years and was the highest in seven- to eight-year-old children, whereas the increase in the cross-correlation of cortical bioelectric potentials in the frontal—occipital direction developed gradually, approaching the definitive level typical of adults by the age of nine to ten years. The results suggest that the central mechanisms of stereognosis, a function important for manual and occupational activities, gradually develop during postnatal ontogeny. Heterochronic involvement of intra- and interhemispheric interactions in the performance of stereognostic task may be related to gradual, heterochronic myelination of commissural and associative pathways.     

An asymmetric producer-scrounger game: body size and the social foraging behavior of coho salmon

A tension between cooperation and conflict characterizes the behavioral dynamics of many social species. The foraging benefits of group living include increased efficiency and reduced need for vigilance, but social foraging can also encourage theft of captured prey from conspecifics. The payoffs of stealing prey from others (scrounging) versus capturing prey (producing) may depend not only on the frequency of each foraging strategy in the group but also on an individual’s ability to steal. By observing the foraging behavior of juvenile coho salmon (Oncorhynchus kisutch), we found that, within a group, relatively smaller coho acted primarily as producers and took longer to handle prey, and were therefore more likely to be targeted by scroungers than relatively larger coho. Further, our observations suggest that the frequency of scrounging may be higher when groups contained individuals of different sizes. Based on these observations, we developed a model of phenotype-limited producer-scrounger dynamics, in which rates of stealing were structured by the relative size of producers and scroungers within the foraging group. Model simulations show that when the success of stealing is positively related to body size, relatively large predators should tend to be scroungers while smaller predators should be producers. Contrary to previous models, we also found that, under certain conditions, producer and scrounger strategies could coexist for both large and small phenotypes. Large scroungers tended to receive the highest payoff, suggesting that producer-scrounger dynamics may result in an uneven distribution of benefits among group members that—under the right conditions—could entrench social positions of dominance.     

Relationship between female body size and demographic parameters inBactrocera Malaysian A (Diptera: Tephritidae)

The effect of body size, as measured by the head width, of the female Bactrocera sp. Malaysian A (kept separately in sexual pairs) on the demographic parameters was investigated in the laboratory under ambient conditions of 28–30°C, 78–85% RH and natural photoperiod. Body size was shown to influence significantly all the demographic parameters. The expectation of life of females at eclosion from pupae was respectively for head widths of 1.6, 1.8, 1.9, 2.0 and 2.1 mm: 76.2, 73.4, 73.8, 102.4 and 115.2 days. The mean number of eggs laid per female in its life time was respectively: 86.4±48.7, 181.8±56.1, 229.7±72.6, 364.3±69.4 and 477.5±109.3 which was significantly different from one another (F=3.73,P<0.05) especially the two smaller sizes from the two larger sizes. The regression line for total eggs laid (Y) against head width (X) was Y=785.2X−1208.7 (R²=0.35,P<0.001). The net reproductive rate (R₀) was respectively 15.8, 34.0, 43.5, 66.9 and 88.8 eggs, while the intrinsic rate of increase (r) was respectivley 0.0435, 0.0538, 0.0670, 0.0665 and 0.0711. The results confirm that for mass rearing purposes, larger females which produce more offspring are to be preferred.     

Seasonal changes in body size,sexual size dimorphism and sex ratio in relation to mating system in an adult odonate community

Seasonal environments impose developmental time constraints on insects which can be reflected in body size and sex ratio. By tracking these two aspects in recently emerged adults of 10 species of an odonate community in a number of lakes, we investigated whether (a) body size in both sexes decreased as the flight season progressed and whether this led to seasonal changes in sexual size dimorphism (SSD); (b) SSD patterns were related to mating systems; (c) biases in sex ratio could be explained by mortality rates associated with the largest sex (e.g. in species with male-biased SSD, a female-biased sex ratio; in species with female-biased SSD, a male-biased sex ratio). Our results indicated that adults in most species, but not all, tend to reach a smaller body size as the season progressed. However, the opposite pattern was found in a few species. Predictions about the relation between SSD and mating systems were confirmed: a female-biased SSD in nonterritorial species and monomorphism for territorial species. However, predictions of biases in sex ratio according to SSD were not met in all species. Interestingly, changes in body size and SSD along the season were lake-specific in two species in which these patterns could be examined. These results, although partially supportive of environmental and sexual selection patterns acting on size and sex ratio as documented in other odonate species, indicate that we are still far from understanding seasonal constrains in these animals.