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The otoliths (ear stones) of fishes are commonly used to describe the age and growth of marine and freshwater fishes. These non-skeletal structures are fortuitous in their utility by being composed of mostly inorganic carbonate that is inert through the life of the fish. This conserved record functions like an environmental chronometer and bomb-produced radiocarbon (14C)—a 14C signal created by atmospheric testing of thermonuclear devices—can be used as a time-specific marker in validating fish age. However, complications from the hydrogeology of nearshore marine environments can complicate 14C levels, as was the case with gray snapper (Lutjanus griseus) along the Gulf of Mexico coast of Florida. Radiocarbon of these nearshore waters is influenced by freshwater input from the karst topography of the Upper Floridan Aquifer—estuarine waters that are 14C-depleted from surface and groundwater inputs. Some gray snapper likely recruited to this kind of environment where 14C levels were depleted in the earliest otolith growth, although age was validated for individuals that were not exposed to 14C-depleted waters to an age of at least 25 years with support for a 30-year lifespan.
For the purposes of this study I am defining West Central Africa largely by the watershed of the Congo River. If the region has a hydrographic center, it is the Lunda Plateau in eastern Angola, a relatively flat region at roughly 1,000 meters elevation, origin of many of the largest effluents of the Congo. This highland continues eastward until it reaches the great range of mountains that define the Rift Valley, and separate it from the Nile system. Because human geography is not always identical to natural geography, there are additions to this defined space.
An important addition is the rivers that drain from the low mountains that define the western end of the Congo watershed that flow westward into the Atlantic Ocean which are included in the study because many political units had borders that straddled the two, such as the Kingdoms of Ndongo and Kasanje, which were regularly engaged on both sides of the Kwango watershed, or the Luyana Kingdom, which lay squarely in the Zambezi River watershed but was in substantial communication with the Lunda Empire.
The death of Nawej II in 1852 marks the end of this history. In some ways, this date, like any other, has only limited significance. One might as easily chose the death of Henrique II in Kongo in 1856, or the death of several other powerful or influential rulers, as the region was not so tightly integrated politically as to give precedence to any one or the other.
But the mid-nineteenth century was a signal turning point for West Central Africa. In 1839 steamships from Europe began making regular stops in Africa, and for the first time in history it was possible to ship bulk commodities cheaply. The Industrial Revolution in Europe had reached a point where production of some vital commodities such as metal goods and textiles were sufficient in themselves to clothe and provide equipment for entire world regions, and export them there. The commodity revolution, the mass import of mundane products, began in earnest with that signal change.
Lunda becomes an important kingdom and begins expanding east and west, Matamba and Kasanje struggle over the Kwango Valley, the Portuguese consolidate their control over the colony of Angola, Kongo enters a period of civil war, and Beatriz Kimpa Vita tries to restore it
Based on substantial new research from primary sources and archives, this accessible interpretative history of West Central Africa from earliest times to 1852 gives comprehensive and in-depth coverage of the region. With equal focus given to both internal histories or inter-state interactions and external dynamics and relationships, this study represents an original approach to regional histories which goes beyond the existing scholarship on the area. By contextualising and expanding its range, to include treatment of the Portuguese colony of Angola, John K. Thornton provides new understandings of significant events, people, and inter-regional interactions which aid the grounding of the history of West Central Africa within a broader context. A valuable resource to students and scholars of African history.
The identification of natural bioactive compounds which can prevent the post-weaning growth check and enhance gastrointestinal health in the absence of in-feed medications is an urgent priority for the swine industry. The objective of this experiment was to determine the effects of increasing dietary inclusion levels of laminarin in the first 14 d post-weaning on pig growth performance and weaning associated intestinal dysfunction. At weaning, ninety-six pigs (8·4 (sd 1·09) kg) (meatline boars × (large white × landrace sows)) were blocked by live weight, litter and sex and randomly assigned to: (1) basal diet; (2) basal + 100 parts per million (ppm) laminarin; (3) basal + 200 ppm laminarin and (4) basal + 300 ppm laminarin (three pigs/pen). The appropriate quantity of a laminarin-rich extract (65 % laminarin) was added to the basal diet to achieve the above dietary inclusion levels of laminarin. After 14 d of supplementation, eight pigs from the basal group and the best-performing laminarin group were euthanised for sample collection. The 300 ppm laminarin group was selected as this group had higher ADFI compared with all other groups and higher ADG than the basal group (P < 0·05). Laminarin supplementation increased villus height in the duodenum and jejunum (P < 0·05). Laminarin supplementation increased the expression of SLC2A8/GLUT8 in the duodenum, SLC2A2/GLUT2, SLC2A7/GLUT7, SLC15A1/PEPT1 and FABP2 in the jejunum and SLC16A1/MCT1 in the colon. Laminarin supplementation reduced Enterobacteriaceae numbers in the caecum (P < 0·05) and increased lactobacilli numbers (P < 0·05), total volatile fatty acid concentrations and the molar proportions of butyrate (P < 0·01) in the colon. In conclusion, 300 ppm laminarin from a laminarin-rich extract has potential, as a dietary supplement, to improve performance and prevent post-weaning intestinal dysfunction.