Diachronic effects of bio-cultural factors on stature and body proportions in British archaeological populations

Humans like all animal species, are subject to Bergmann\u27s (1847) and Allen\u27s (1877) environmental rules which summarize physical adaptations to the natural environment. However, humans are in addition cultural animals and other bio-cultural factors, such as social, economic and political status, general health, and nutrition, have a noticeable influence on stature and body proportions. Importantly, socio-economic status has a powerful influence on stature, which has been used to elucidate status differences in past societies (Bogin and Loucky, 1997; Floud et al., 1990; Schutkowski, 2000a). Furthermore, bio-cultural factors influence all dimensions of the human body, including weight, relative limb length, and relative length of the different limb segments. Given minimal migration and shared natural environments, all populations in this study, coming as they do from the last 2000 years of English history, should demonstrate similar morphology (c.f. Ruff, 1994) if climatic variables were the only influence on stature and body proportions. In order to assess such bio-cultural factors in individuals from archaeological populations, skeletal populations from sites such as known leprosaria and medieval hospitals, rural and urban parish cemeteries, victims from the battle of Towton in A.D. 1461, and individuals from monastic cemeteries were analysed. The osteometric data from these populations were assessed for within and between population variability and indicate effects of bio-cultural factors on attained body proportions and stature. The results indicate a strong relationship between bio-cultural factors and body proportions, body mass index, prevalence of pathologies, sexual dimorphism, secular trend, and general stature from Roman times to the post-medieval period. The usefulness of stature, weight, and physical indices as markers of the bio-cultural environment is demonstrated. The main findings include: a greater sensitivity to external stressors in the males rather than the females of the analysed populations, rendering male statures more susceptible to varying bio-cultural conditions

Heterogeneity in the Cognitive Manifestations of Prosopagnosia - the Study of a Group of Single Cases

The aim of this study was to gain a better understanding of prosopagnosia by testing a group of prosopagnosic subjects on the same set of tests. A clinical test battery has been described by Bruyer and Schweich (1991), organised on the basis of the cognitive model of face recognition proposed by Bruce and Young (1986) and including Ellis's (1986b) suggestion of a facial decision stage. The battery consists of 6 basic tests tapping the various loci of the cognitive architecture, and 11 optional subtests provided to explore in more detail any defects that may be detected in the basic tests. The battery was administered to 9 prosopagnosic subjects as well as to a group of 72 normal subjects. The prosopagnosic subjects' performances illustrate that prosopagnosia is not a unitary syndrome and they are used to support several dissociations provided by the cognitive models of face recognition

Modélisation d'un échangeur d'ions : possibilités et limites des modèles disponibles — Proposition d'un modèle prenant en compte les limitations diffusionnelles et la dispersion hydrodynamique

En modélisant les équilibres résine/solution à l'aide de coefficients de sélectivité supposés constants, les étapes de diffusion externe et interne par des systèmes du premier ordre et la dispersion hydrodynamique par le modèle des mélangeurs en cascade avec recyclage interne, nous proposons un modèle simple, permettant de prévoir le fonctionnement d'un échangeur d'ions. A partir de paramètres que l'on peut soit déterminer à l'aide d'expériences simples, soit estimer à partir de données de la littérature, ce modèle permet de très bien représenter des courbes de perçage obtenues expérimentalement pour diverses solutions d'alimentation

Race categorization and face recognition stages in the processing of laterally displayed unknown faces.

Bruyer and Dussart (1985) have recently shown that the "race effect", i.e. the difficulty in recognizing faces issuing from an ethnic group different from that of the subject, is limited to the right visual field. They suspected familiarization to be responsible for this asymmetry. In Exp. I, we tested this hypothesis by repeating the experiment of Bruyer and Dussart with a greater number of trials. A sample of 16 subjects were given the task of recognizing black and white faces laterally displayed for 180 msec. No laterality effect appeared, and the race effect was observed to an equal degree in each hemifield at all stages of the experimental session. It could thus be that various kinds of familiarization must be distinguished. In Exp. II, with 16 new subjects, the black and white faces were mixed so that the subjects had first to perform racial categorization, then a recognition. This time, an advantage of the left field appeared, the race effect was larger in the right than in the left field, and the race effect decreased with familiarization in the left field only. Two complementary experiments with 24 and 16 subjects showed that this phenomenon was not explainable by laterality effects in the early racial decision operation, but well by a lateralized effect of tasks requirements

The role of vitamin E in the susceptibility of rat lung and liver microsomes to iron-stimulated peroxidation.

The production of thiobarbituric acid-reactive substances (TBA-RS) and ethane, two markers of the lipid peroxidation process, was evaluated in rat lung and liver microsomal membranes incubated in the presence of either ferrous ions or a mixture of ferric ions and ascorbate. Microsomal fractions isolated from lung tissue were more resistant than those isolated from the liver. Compared to Fe2+, the association of Fe3+/ascorbate seemed to be totally ineffective in stimulating peroxidation of lung microsomes. The fatty acid profile of lung and liver microsomal membranes could not be responsible for their different susceptibility to free radical degradation. The microsomal fraction isolated from lung showed a higher vitamin E concentration than the liver. The importance of vitamin E in protecting lung membranes was assessed by using lung and liver isolated from vitamin E-deficient and vitamin E-supplemented rats. For both lung and liver microsomal fractions an inverse relationship between vitamin E concentrations and the extent of lipid peroxidation was observed. However, although the vitamin E concentrations in lung and liver microsomes isolated from rats submitted to a vitamin E-deficient diet were not different, lung microsomes still exhibited a lower production of TBA-RS and ethane than liver. In addition to vitamin E, other factors must be involved to explain the resistance of lung microsomes to lipid peroxidation

Effect of oxygen concentration on production of ethane and thiobarbituric acid-reactive substances by peroxidizing lung and liver homogenates and formation of ethanol by peroxidizing docosahexaenoic acid preparations under hyperoxic conditions.

The oxygen dependence of ethane formation was investigated in rat lung and liver homogenates, incubated in sealed flasks, in which the peroxidation was stimulated by the addition of ferrous ions. For both tissues, the production of ethane was maximal under a 20% oxygenated gas phase, while hyperoxic conditions led to a decreased ethane in the gas phase. The formation of thiobarbituric acid-reactive substances (TBA-RS), another marker of the lipid peroxidation process, in the homogenates of lung and liver was strongly stimulated at 100% compared to 20% oxygen. Experiments were also carried out on iron-stimulated peroxidation of pure docosahexaenoic acid preparations, which under air led to a large production of ethane. As for tissue homogenates, the TBA-RS content was increased in the presence of 100% oxygen. Those conditions, however, did not induce an increase in ethane production but led to the formation of ethanol. Therefore, the quenching of ethyl radical by molecular oxygen seems to be a very attractive hypothesis to explain the lack of increased ethane production in favor of ethanol when iron-induced lipid peroxidation was stimulated by oxygen

Scale up of slurry bubble reactors

Bubble column reactors are finding increasing use in industrial practice. They are in particular appropriate to carry out highly exothermic reactions, such as methanol synthesis or Fischer-Tropsch synthesis of conversion of synthesis gas to liquid paraffins. Industrial process require important volumes of reactors, the reactor diameter can reach 10 m. To control the reaction temperature, internal heat-exchange tubes (vertical tubes) are inserted inside the reactor. This study deals with the effects of scale and the presence of internals on hydrodynamic characteristics, for scale-up purposes based on experiments in cold mockups. Our study shows that the liquid recirculation intensity depends strongly on the column diameter whereas the gas holdup is slightly affected. Two methods are proposed to predict scale effect on liquid velocity: an empirical correlation proposed in the literature and a phenomenological model. Internals guide liquid: the large scale recirculation increases but fluctuations of liquid velocity decrease. Therefore the mixing of liquid is significantly affected by the presence of internals and is not well described by the standard mono dimensional axial dispersion model. A two-dimensional model, taking into account a radially dependent axial velocity profile and both axial and radial dispersion, is therefore developed to describe the liquid mixing in a bubble column with internals