The Zambezi River in Moçambique

SUMMARY. Surveys of the physico-chemical status of the River Zambezi in Moçambique were conducted between April 1973 and May 1974, to characterize the river prior to the closure of the Cabora Bassa Dam and to provide baseline data from which future changes in the river ecosystem can be followed. The temperature of the river water increases by about 3°C from Lake Kariba to the sea, and with an average pH of 7.8 the water is slightly more alkaline than Kariba Dam water. The river is well oxygenated with no sign of hydrogen sulphide. Transparency is generally very low and changes are mainly determined by the floods of local tributaries. The overall average total alkalinity is 55 mg 1^?1 CaCO₃, with no regular seasonal variation, average concentrations of chloride and sulphate are respectively, 5.4 mg 1^?1 Cl^? and 5.3 mg 1^?1 SO^2-₄. They increase under both the influence of the ionically rich Shire River and the sea; the latter due to vertical mixing. Total hardness and calcium hardness behave in a similar way, while conductivity and silica concentrations increase slightly until the Zambezi—Shire confluence, at which point, conductivity increases by 25% to an average peak value of 153 μS cm^?1, and silica decreases by 15% to a minimum average value of 15.5 mg 1^?1 SiO₂. Ammonia and nitrate concentrations show a clear seasonal variation, with respectively, minimum dry season and maximum wet season average values of about 0.05 mg 1^?1 and 0.3 mg 1^?1. The overall average concentration of nitrite is 0.004 mg 1^?1. Orthophosphate in the river is mostly affected by Lake Kariba, though other sources are also of some importance. Maximum average concentrations of about 0.4 mg 1^?1 PO^3-₄ were recorded during the dry season after the overturn of Lake Kariba. The concentration of dissolved metals is mainly determined by the outflow of Kariba and by the Shire River, with only K and Mg apparently affected by the outflow from Lake Kafue. It is concluded that the water quality of the Middle Zambezi is mainly determined by the Kariba Dam, with the Kafue Dam playing a minor role. At the time of the pre-impoundment survey, the main impact on water quality of the Lower Zambezi came from the Shire River. With the addition of yet another large reservoir on the Zambezi, in the form of Cabora Bassa, together with the appreciable effect of tributary rivers on the lake, and the likely increased impact of the Shire River on the now more regulated river, the quality of the Lower Zambezi is expected to alter considerably, with concomitant ecological changes.     

The limnology of selected Guatemalan Lakes

Hydrobiologia - During the summer of 1969, fourteen Guatemalan lakes were sampled, including eight in the lowland northern province of Peten and six in southern Guatemala. The majority of the Peten...     

Children's diurnal cortisol activity during the first year of school

The present study examined 4- to 5-year-old British children's diurnal cortisol activity during their first year of school. The children's cortisol was measured before enrollment (baseline), upon enrollment, and both 3 and 6 months after enrollment. On each day, cortisol was sampled four times, providing information about the diurnal amount of cortisol secreted (AUC_G). Mixed-effect models were constructed to examine the way children's cortisol fluctuated over the course of the school year. Physiological activity was greater 3 months after enrollment, suggesting that some children reacted more to the challenge of school later than they did initially. Implications and suggestions for transitional practices and future research are discussed.     

Wood ontogeny during the first year of hybrid poplar development

During the first year of hybrid poplar development, we assessed radial growth dynamics quantified by the proportion of secondary xylem tissue within the stem area, the vessel area percentage, the content of both lignin and cellulose, the lignin monomeric composition, and the macromolecular properties of cellulose. The intraannual radial growth dynamics in the proportion of secondary xylem tissue was fitted by the Gompertz regression line whereas changes in the vessel area percentage were fitted maximally by a cubic regression line. Under constant temperature and photoperiod, this study revealed that nonlinear patterns of radial growth dynamics are the result of a developmental programme which drives cambial activity and ageing. The increased proportion of guaiacyl units found may be important for the greater stability of the lignin structure in the first year of hybrid poplar development. The tensile strength of juvenile wood was ensured by the trade-off between a slight increase in the degree of polymerization of cellulose and a slight decrease in the content of cellulose during ageing.     

The development of human gut microbiota fermentation capacity during the first year of life

Fermentation capacity of microbial ecosystems intrinsically depends on substrate supply and the ability of a microbial community to deliver monomers for fermentation. In established microbial ecosystems, the microbial community is adapted to efficiently degrade and ferment available biopolymers which is often concurrently reflected in the richness of the microbial community and its functional potential. During the first year of life, the human gut microbial environment is a rather dynamic system that is characterized by a change in physiological conditions (e.g. from aerobic to anaerobic conditions, physical growth of the gastrointestinal tract, development of the intestinal immune system) but also by a change in nutrient supply from a compositionally limited liquid to a diverse solid diet, which demands major compositional and functional changes of the intestinal microbiota. How these transitions link to intestinal microbial fermentation capacity has gained comparatively little interest so far. This mini-review aims to collect evidence that already after birth, there is seeding of a hidden population of various fermentation organisms which remain present at low abundance until the cessation of breastfeeding removes nutritional restrictions of a liquid milk-based diet. The introduction of solid food containing plant and animal material is accompanied by an altering microbiota. The concurrent increases in the abundance of degraders and fermenters lead to higher intestinal fermentation capacity indicated by increased faecal levels of the final fermentation metabolites propionate and butyrate. Recent reports indicate that the development of fermentation capacity is an important step during gut microbiota development, as chronic disorders such as allergy and atopic dermatitis have been linked to lower degradation and fermentation capacity indicated by reduced levels of final fermentation metabolites at 1 year of age.     

The detritus limnology of sathiar reservoir

In Sathiar reservoir detritus plays a significant role as a means of promoting exchange between the bottom sediments and the column of water. The means by which recycling of the various components in the aquatic biosphere takes place are discussed. The amount of energy stored or that which is bound in detritus is substantially supported by the co-occurrence of chlorophyll, total phosphorus and total nitrogen in the detritus.     

The physico-Chemical limnology of Loch Lomond

Loch Lomond, the largest freshwater lake in Britain, is physically divided into a number of distinct basins by geological structures. The northern part of the loch is long, narrow and deep whilst the southern area is broad and shallow with many islands scattered throughout it.The water chemistry of the loch is dictated by the geology of catchment and the quality of the rivers flowing into it. The two major rivers, the Falloch and the Endrick Water, are both of good quality with low nutrient content. Consequently, the loch is regarded as oligotrophic, though the southern area verges towards being mesotrophic.     

Vocal-speech development of the child during the first year of life

The study aimed at investigation into the first step of language acquisition by Russian children and the imitation process as a possible mechanism of mastering the language through the sounds specific for their native language. On the basis of spectrographic, phonetic, and listener's analysis of the sounds infants, the beginning of shaping of the phonologic system in Russian language, was shown. It was shown that, during imitation of mother's voice, children acquire articulation skills and sound utterances approximating a phoneme category of the native language. The data obtained indicate that interaction between mother and child fulfills the function of learning transmitting a language data on the tongue trame.     

Incidence of lead dislodgement,malfunction and perforation during the first year following device implantation

Background

The number of cardiac rhythm device implantations has been growing fast due to expanding indications and ageing of the population. Complications of implantation were rare in the trials. However, these involved small numbers and selected patients. Prospective real-life data are necessary to assess cardiac device implantation procedure-related risks.

Objective

To determine the incidence and predictors of lead-related re-intervention in a Dutch high-volume teaching hospital.

Methods

Data from all patients who underwent cardiac rhythm device implantation between January 2010 and December 2011 were collected in a prospective registry. At least 1 year of follow-up regarding re-intervention was available for all patients. Lead-related reasons for re-intervention were categorised into lead dislodgement, malfunctioning or perforation.

Results

One thousand nine hundred twenty-nine devices including 3909 leads were implanted. In 595 patients (30.8 %) a CRT-D/P was implanted. Lead-related re-intervention was necessary in 86 (4.4 %) patients; it was more common in younger and male patients, and due to either lead dislodgement (66 %), malfunctioning (20 %) or perforation (18 %). Coronary sinus lead dislodgement or malfunctioning was 1.4 %. Right atrial dislodgement (1.9 %, p < 0.001) or ICD lead dislodgement (1.8 %, p = 0.002) was more common than right ventricular dislodgement (0.3 %). The incidence of lead malfunctioning was higher (0.8 %) in ICD leads. An apical position of the right ventricular lead and lateral wall position of the right atrial lead were related to cardiac perforation.

Conclusions

The incidence of lead-related re-intervention was comparable with the literature. The majority of re-interventions were due to lead dislodgements, particularly with right atrial and ICD leads. Re-intervention due to coronary sinus lead dislodgement was rare.     

Antibiotic therapy of Salmonella infection in infants during the first year of life and methods if its correction]

The efficacy of antibiotic therapy of salmonellosis was studied and functional activity of peripheral blood leukocytes from electron microscopic data was estimated in 200 infants. It was shown that the use of antibiotics in combination with immunostimulants such as leukocyte mass, lysozyme and prodigiozan in complex therapy of salmonellosis in infants had a favourable effect on both the time course of the clinical signs and the functional state of the neutrophil leukocytes. The duration of the treatment decreased by 6.14 +/- 0.34 days and repeated isolation of the pathogen from the host appeared to be less frequent.     

The physical-chemical limnology of a desert reservoir

The physical-chemical limnology of a desert lake in central Arizona was investigated from February 1971–July 1973. The reservoir was found to be a warm-monomictic, eutrophic lake which exhibited pronounced thermal stratification during the summer months. Surface water temperatures ranged from a minimum of ca. 9 C in January to a maximum near 30 C in July–August. Chemically the lake may be described as a hard water lake of moderately high alkalinity and salinity. The concentration of the principal ions was affected significantly by precipitation run-off. The primary nutrients N and P were subject to considerable seasonal variability, being influenced most by precipitation and phytoplankton abundance. Trace element concentrations were low and showed comparatively little fluctuation during the study.