On some models for developmental systems Part I. Organism structure on the basis of elementary transformations

A great number of organism development processes can be accounted for by the elementary mechanisms of cell partition and cell transformation. In the present article an analytical method is presented which emphasizes the link that exists between the generating word of an organism (in the language consisting of the possible cell transformations) and the successive structures of the developmental process. The viewpoints of analysis (types of structures generated by a given type of word) and of synthesis (type of word generating a given type of structure) are considered. As an illustration of the method models of development are constructed which have already been proposed empirically to account for two types of plant development.     

On some models for developmental systems Part IX. Generalized generating word and genetic code

The model for developmental systems used by the present authors in the foregoing eight parts is generalized and compared to biological facts concerning DNA.     

HPLC determination of polycyclic aromatic hydrocarbons (PAHs) in the littoral urban sewage area of cortiou (Marseille,France)

A selective method for determining polycyclic aromatic hydrocarbons (PAHs) in sediments using solid‐phase extraction and RP‐HPLC with fluorescence and UV detection is described. The complete analytical method is used to surface sediments from the creek of Cortiou (France). Sewage from the urban area of Marseille is delivered to the creek. PAH levels in sediments (µg/g) range between 2.251 µg/g (for the benzo(a)anthracene) and 相似文献   

Evolution in the composition of human skin surface lipids during their accumulation on scalp and hair

Qualitative examination of human surface lipids collected using a surfactant solution shows that there are no significant differences between individuals when the samples are collected after one day, starting from clean hair and scalp. On the contrary, samples collected after 4 days reveal discrepancies within the population, related to the oily hair symptom.
An evolution in the composition of the recovered mixture occurs during the 1–4 days accumulation period, which mainly results in an increased unsaturation of the total (free + glycerides) fatty acids fraction isolated after saponification.
A two-step mechanism is proposed to account for the observed evolution: in a first step, free fatty acids are cleaved from glycerides by the well known enzymatic hydrolysis. Analytical determinations show that this process is structure dependant, the straight chain saturated acids being more readily hydrolyzable than the unsaturated and branched chain species. In a second step, free fatty acids are immobilized on the keratinic fibers, by a process which involves the formation of Ca salts.
This evolution results in a decreased viscosity of the skin surface lipids and in an increase of the low temperature melting fraction of the mixture. Its extent is more or less pronounced, depending upon the individuals. Subjects who exhibit extensive evolution are affected by the oily hair symptom.
Evolution de la composition des lipides superficiels humains durant leur accumulation sur le scalp et les cheveux     

AGGREGATION,EMERGENCE AND IMMERGENCE IN HIERARCHICALLY ORGANIZED SYSTEMS

Abstract

The aim of this work is to show that couplings between fast micro-dynamics and slow macro-dynamics can make emerge global properties. Emergence corresponds to a bottom-up coupling, that is to the effect exerted by a micro-level at a macro-level. Immergence corresponds to the inverse process, that is to an up-down coupling. As an example, we present a prey-predator model with different time scales in a heterogeneous environment. A fast time scale is associated to the migration process on spatial patches and a slow time scale is associated to growth and interactions between the populations. Preys go on spatial patches where resources are located and where predators can attack them. The efficiency of predators is patch-dependent. Perturbation theory is used in order to aggregate the initial system of ordinary differential equations for patch sub-populations into a macro-system of two differential equations governing total populations. First, we study a case of density-independent migrations, for which no emergence occurs. Then, we study some examples of density-dependent migrations. In this case, emerging properties appear at the population level.     

Bioavailability of Calcium Citrate Malate Added to Microbial Phytase-Treated, Hydrothermally Cooked Soymilk

Effects of microbial phytase on bioavailability of calcium added to corn/soy diets were investigated in chickens. No effect (P > 0.17) of phytase was found for weight gain, feed intake, tibia/body weight, ash%, and ash Ca% when calcium citrate malate (CCM) was added to corn/soybean meal and corn/hydrothermally cooked (HTC) soymilk diets. Using calcium carbonate in corn/HTC soymilk diets, means for weight gain, feed intake, tibia/body weight, and ash% were less (P < 0.05) without phytase. We hypothesize that CCM is less amenable to the formation of calcium phytate complexes than are other calcium salts and, therefore, should be more effective for fortification of soymilk products.     

DESIGN AND TUNING OF A FUZZY CONTROLLER FOR INDOOR AIR QUALITY AND THERMAL COMFORT MANAGEMENT

This paper presents the development and testing of a multi objective fuzzy controller. It is dedicated to the control of thermal comfort and indoor air quality while minimising energy consumption and reducing instabilities are other constraints for this controller. After a brief introduction on the difficult task of indoor climate control, the test cell and its corresponding model is described in the second section. The model has been developed within TRNSYS. Section 3 describes the architecture of the fuzzy controller applied to these control objectives in the test cell. A hierarchical architecture has finally been selected since it is a very flexible architecture and it results in reducing the total number of fuzzy rules. The rule optimisation technique, based on genetic algorithms is also presented in the third section. Simulation results are finally presented. They prove that, after optimisation, the fuzzy controller greatly outperforms a typical ON-OFF controller on all control criteria. Energy consumption is in particular reduced by more than 10%. The fourth section of this chapter presents field experiments among 20 subjects of both ON-OFF control and fuzzy control. If major differences are not observed on the thermal comfort and indoor air quality point of view, these experiments however illustrate the importance of on-line tuning of specific fuzzy rules.     

Energy Catabolism in Rabbit Muscle as Affected by Brine Injection: 31P NMR Studies

The energy catabolism in brine-injected muscles was examined by ³¹P Nuclear Magnetic Resonance (NMR) spectroscopy. Immediately after death of rabbits, brines containing NaCl, with or without pyrophosphate, were injected into the arterial system. ³¹P NMR spectra at 4°revealed marked heterogeneity in postmortem catabolism due to brine diffusion. The heterogeneity of the Pi signal for injected muscles reflected the existence of muscle areas with different intracellular pH values. This observation suggested an increase in rate of glycolysis for fibers experiencing brine. The heterogeneity of brine diffusion seemed to be affected by method of injection.     

Nonlinear Electrical Properties of Grain Boundaries in an Oxygen-Ion Conductor (CeO2· Y2O3)

The ceria-yttria solid solution is a good anionic conductor. In polycrystalline ceramics, the complex impedance spectroscopy shows clearly the existence of a significant additional resistance associated with the grain boundaries. In this paper a theoretical analysis of the ac response in the nonlinear regime is developed. In particular the current-voltage and capacitance-voltage characteristics of the grain boundaries are derived. For the material investigated the former is well fitted by the Poole-Frenkel law while the capacitance is voltage independent. These results are in agreement with microscopic STEM observations of a silica-rich second phase.