The Control of Dynamical Systems - Recovering Order from Chaos -

Following a brief historical introduction of the notions of chaos in dynamical systems, we will present recent developments that attempt to profit from the rich structure and complexity of the chaotic dynamics. In particular, we will demonstrate the ability to control chaos in realistic complex environments. Several applications will serve to illustrate the theory and to highlight its advantages and weaknesses. The presentation will end with a survey of possible generalizations and extensions of the basic formalism as well as a discussion of applications outside the field of the physical sciences. Future research avenues in this rapidly growing field will also be addressed.Comment: 18 pages, 9 figures. Invited Talk at the XXIth International Conference on the Physics of Electronic and Atomic Collisions (ICPEAC), July 22-27, 1999 (Sendai, Japan

At-risk serum cholesterol profile at both ends of the nutrition spectrum in West African adults? The Benin study

Low HDL-cholesterol (HDL-C), using as cut-offs 1.03 mmol/L in men and 1.29 mmol/L in women, was observed in more than 25% apparently healthy adults (n = 541) in a cross-sectional study on nutrition transition and cardiometabolic risk factors (CMRF) in Benin, West Africa. Both overweight/obesity (35.3%) and underweight (11.3%) were present, displaying the double burden of malnutrition. We examined in more depth the association of low HDL-C with nutrition and with other CMRF. Metabolic syndrome components were assessed, plus the ratio of total cholesterol (TC)/HDL-C and serum homocysteine. Insulin resistance was based on Homeostasis Model Assessment. We also measured BMI and body composition by bio-impedance. Dietary quality was appraised with two non-consecutive 24 h recalls. Low HDL-C was associated with much higher TC/HDL-C and more abdominal obesity in men and women and with more insulin resistance in women. The rate of low HDL-C was highest (41.9%) among the overweight/obese subjects (BMI ≥ 25), but it also reached 31.1% among the underweight (BMI < 18.5), compared with 17.3% among normal-weight subjects (p < 0.001). Lower dietary micronutrient adequacy, in particular, in vitamins A, B3, B12, zinc and calcium, was associated with low HDL-C when controlling for several confounders. This suggests that at-risk lipoprotein cholesterol may be associated with either underweight or overweight/obesity and with poor micronutrient intake

Microbiology and atmospheric processes: Biological, physical and chemical characterization of aerosol particles

The interest in bioaerosols has traditionally been linked to health hazards for humans, animals and plants. However, several components of bioaerosols exhibit physical properties of great significance for cloud processes, such as ice nucleation and cloud condensation. To gain a better understanding of their influence on climate, it is therefore important to determine the composition, concentration, seasonal fluctuation, regional diversity and evolution of bioaerosols. In this paper, we will review briefly the existing techniques for detection, quantification, physical and chemical analysis of biological particles, attempting to bridge physical, chemical and biological methods for analysis of biological particles and integrate them with aerosol sampling techniques. We will also explore some emerging spectroscopy techniques for bulk and single-particle analysis that have potential for in-situ physical and chemical analysis. Lastly, we will outline open questions and further desired capabilities (e. g., in-situ, sensitive, both broad and selective, on-line, time-resolved, rapid, versatile, cost-effective techniques) required prior to comprehensive understanding of chemical and physical characterization of bioaerosols

Use of farm grown cereal/protein mixes by lactating dairy cows in a winter diet

We compared the use of three farm grown cereal/protein mixes (oat/fava bean, barley/lupin, triticale/pea), that were used to complement lactating dairy cow diets based on hay consisting of alfalfa/orchard grass and perennial grassland. The trial took place in 2007 at the INRA experimental station of Mirecourt, where an organic mixed-crop dairy system is being prototyped. The experiment was carried out in a Latin square with three groups of eight cows (50% Holstein, 50% Montbéliarde). The cows were fed 4 kg/cow/day of one of the three cereal/protein mixes, 8 kg DM/cow/day of alfalfa/orchardgrass hay, and permanent grassland hay ad libitum. The three diets were indicative of the animals’ needs. Diets had no significant effect on milk production (20.3 kg/cow/d) and milk fat content (41.3 g/kg). However, dairy cows fed with the oat/fababean mix had a significantly lower protein content in their milk. This is the result of: (i) a nitrogen surplus in relation to energy, and (ii) a lower starch content compared to the two other diets. Therefore, in organic mixed-crop dairy systems with forages that are rich in nitrogen, the choice to cultivate mixtures of cereal/pulses and the composition of these mixtures must be primarily based on their agronomic interest and not on their zootechnical one since they are not essential to a balanced animal diet

Mesenchymal Stem Cells Promote Oligodendroglial Differentiation in Hippocampal Slice Cultures

We have previously shown that soluble factors derived from mesenchymal stem cells (MSCs) induce oligodendrogenic fate and differentiation in adult rat neural progenitors (NPCs) in vitro. Here, we investigated if this pro-oligodendrogenic effect is maintained after cells have been transplanted onto rat hippocampal slice cultures, a CNS-organotypic environment. We first tested whether NPCs, that were pre-differentiated in vitro by MSC-derived conditioned medium, would generate oligodendrocytes after transplantation. This approach resulted in the loss of grafted NPCs, suggesting that oligodendroglial pre-differentiated cells could not integrate in the tissue and therefore did not survive grafting. However, when NPCs together with MSCs were transplanted in situ into hippocampal slice cultures, the grafted NPCs survived and the majority of them differentiated into oligodendrocytes. In contrast to the prevalent oligodendroglial differentiation in case of the NPC/MSC co-transplantation, naive NPCs transplanted in the absence of MSCs differentiated predominantly into astrocytes. In summary, the pro-oligodendrogenic activity of MSCs was maintained only after co-transplantation into hippocampal slice cultures. Therefore, in the otherwise astrogenic milieu, MSCs established an oligodendrogenic niche for transplanted NPCs, and thus, co-transplantation of MSCs with NPCs might provide an attractive approach to re-myelinate the various regions of the diseased CNS. Copyright (C) 2009 S. Karger AG, Base

Hypertriglyceridemic waist identifies HIV+ men and women at increased cardiometabolic risk

Screening for increased waist circumference and hypertriglyceridemia (the hypertriglyceridemic-waist phenotype) is an inexpensive approach to identify patients at risk of coronary artery disease in apparently healthy individuals who may be at increased risk of type 2 diabetes and coronary heart disease because of an excess of intra-abdominal (visceral) fat. We examined the ralationship between the hypertriglyceridemic-waist and selected cardiometabolic risk factors in HIV individuals