Challenges and opportunities for smallholder livestock production in post-conflict South Kivu, eastern DR Congo

A survey on smallholder livestock production with emphasis on monogastric animals was conducted in 20 villages of seven so-called ‘groupements’ of South Kivu province in DR Congo, situated along a north to south-west axis with the town of Bukavu in the center. This land adjacent to Lake Kivu is located at elevations ranging around 900–1900 m asl, experiencing tropical highland climate. A diagnostic survey helped to rapidly obtain in-depth knowledge of constraints and opportunities in this environment. Correspondence analysis and multiple regression analysis were used to investigate the association of production constraints with particular livestock species and to understand the factors that govern the number of livestock that people owned (converted to tropical livestock units [TLU]), respectively. Responses of 112 informants demonstrated that livestock is an integral part of the region’s mixed farming systems. Low livestock numbers per household at present reflect the poverty as a consequence of recent violent conflicts. Currently, farmers focus on small livestock, like poultry, swine, cavies (i.e., Guinea pigs) and rabbits. Families keep livestock to accumulate household reserves that are strongly invested in children’s education. Major issues of animal husbandry were related to animal diseases and lack of feed resources, particularly in the dry season. Lack of feed or forages were unrelated to a particular livestock species. Livestock holdings depended on animal diversity, location, land size available and respondents’ education level. The potential introduction of improved forages is challenged by their dry-season tolerance, compatibility with cropping on small farms; and people’s readiness to cultivate forages

Mathematical surprises and Dirac's formalism in quantum mechanics

By a series of simple examples, we illustrate how the lack of mathematical concern can readily lead to surprising mathematical contradictions in wave mechanics. The basic mathematical notions allowing for a precise formulation of the theory are then summarized and it is shown how they lead to an elucidation and deeper understanding of the aforementioned problems. After stressing the equivalence between wave mechanics and the other formulations of quantum mechanics, i.e. matrix mechanics and Dirac's abstract Hilbert space formulation, we devote the second part of our paper to the latter approach: we discuss the problems and shortcomings of this formalism as well as those of the bra and ket notation introduced by Dirac in this context. In conclusion, we indicate how all of these problems can be solved or at least avoided.Comment: Largely extended and reorganized version, with new title and abstract and with 2 figures added (published version), 54 page

Solid state polymorphism of liquid crystals in confined geometries

Solid polymorphism of 4-alkyl-4’-cyanobiphenyl (nCB) was studied so far as a function of thermal history. In this paper we show that metastable solid phases of 4-octyl-4’-cyanobiphenyl (8CB) are also formed when the mesogens are confined in porous silica matrices and we study their structure by neutron diffraction and by Raman spectroscopy. Three metastable solid states are identified : one crystalline phase K’, two frozen-in smectic-like phases K s and K′ s . We discuss the relation between the structure of the metastable solid phases and that of the mesomorph phases

Monolithic porous glasses with controlled mesopore size

Mesoporous sol-gel glasses may play the role of host materials to study the effect of confinement on fluid properties. A method based on a peculiar drying procedure of silica gels, followed by their partial densification by a heat treatment is described. Monolithic mesoporous glasses with a porosity exceeding 50%, a well defined pore size and a controlled surface roughness are obtained. N2 adsorption-desorption and Small Angle X-ray Scattering techniques are used to study the porous and solid texture, and the inner surface roughness of these materials. Various samples of narrow pore size distribution with half width at half height under 2nm, and mean pore size below 25nm are obtained

Sustainable management of metallurgical forest on Mont Lozère (France) during the Early Middle Ages

International audienceMont Lozère, located in the French Massif Central region, provides an exceptional context in which to research the impact that charcoal production and metallurgy had on woodlands, along with the role that these activities played in changing the mountain landscape. This study provides an insight into the land use, forest management methods and metallurgical practices in the area during the Middle Ages (11th to 15th centuries). Medieval charcoal burning platforms, archaeological remains that have often been neglected in the past as a source of historical information, along with nearby smelting sites, were identified, sampled and analysed. In this paper, spatial analyses, radiocarbon dating and anthracological and dendro-anthracological studies have been combined in a unique manner. The results reveal that charcoal burners practiced beech coppicing, where the species and diameter of wood used remained the same over a period of four centuries. It is proposed that this form of metallurgical forest management be considered an early example of a sustainable utilisation of natural resources