Demographic trends in Sub-Saharan Africa

The study of demographic trends in sub-Saharan Africa though crucial in the assessment of the impact of population size and growth on the overall socio-economic development in the region, has received the least attention due to lack of reliable data for most of the countries. This paper focuses on the utilization of available data secured through population censuses and demographic surveys particularly the World Fertility Survey to ascertain trends in fertility and mortality. The estimates derived from the above sources should be interpreted with caution since they suffer from diverse deficiencies in the data base particularly coverage, content and consistency. It is apparent, though debatable, from the available estimates that fertility has increased in some countries--Kenya and Cameroon; has remained almost stable in Benin, Ivory Coast and Lesotho; and has slightly declined in Ghana. The underlying factors with regard to the apparent increase hinge on the improvement in the socio-economic indicators i.e. education and health services; relaxation of traditional controls i.e. breastfeeding and post-partum abstinence; and a reduction in the level of sterility. As far as trends in mortality are concerned, the estimates posit a decline in both infant and child mortality in Kenya, Benin and Ivory Coast; infant mortality in Cameroon; and child mortality in North Sudan and Senegal. Overall mortality levels are high in Western and Central Africa and low in Eastern and Southern Africa

The NCTM Standards: Implementation

In 1989 the National Council of Teachers of Mathematics published the Curriculum and Evaluation Standards for School Mathematics. The NCTM standards provides benchmark statements about specific aspects of the curriculum and about evaluation against which school divisions can judge their own specific curricula. The Standards has been a major focus of mathematics education since 1990. In the fall of 1992 the Metropolitan Educational Research Consortium undertook a study to determine the extent to which local schools were implementing the NCTM Standards. The study of the schools in the Consortium focused on the broad themes of the Standards document: mathematics as problem-solving, mathematics as communication, mathematics as reasoning, and mathematical communication. To teach with these four standard in mind is to teach in a Standards-oriented manner. This report summarizes the finding of three data sources collected from elementary, middle, and secondary school teachers and principals in the MERC school divisions: a survey of teachers, a survey of principals, and focus group interviews of selected teachers. The questions and discussions explore awareness of the Standards, classroom practices, and aids the obstacles to implementation

Radiative capture rates at deep defects from electronic structure calculations

We present a methodology to calculate radiative carrier capture coefficients at deep defects in semiconductors and insulators from first principles. Electronic structure and lattice relaxations are accurately described with hybrid density functional theory. Calculations of capture coefficients provide an additional validation of the accuracy of these functionals in dealing with localized defect states. We also discuss the validity of the Condon approximation, showing that even in the event of large lattice relaxations the approximation is accurate. We test the method on GaAs:$V_\text{Ga}$-$\text{Te}_\text{As}$ and GaN:C$_\text{N}$, for which reliable experiments are available, and demonstrate very good agreement with measured capture coefficients.Comment: 6 pages, 2 figure

Synthesis of Novel Aza‐aromatic Curcuminoids with Improved Biological Activities towards Various Cancer Cell Lines

Curcumin, a natural compound extracted from the rhizomes of Curcuma longa, displays pronounced anticancer properties but lacks good bioavailability and stability. In a previous study, we initiated structure modification of the curcumin scaffold by imination of the labile -diketone moiety to produce novel -enaminone derivatives. These compounds showed promising properties for elaborate follow-up studies. In this work, we focused on another class of nitrogen-containing curcuminoids with a similar objective: to address the bioavailability and stability issues and to improve the biological activity of curcumin. This paper thus reports on the synthesis of new pyridine-, indole-, and pyrrole-based curcumin analogues (aza-aromatic curcuminoids) and discusses their water solubility, antioxidant activity, and antiproliferative properties. In addition, multivariate statistics, including hierarchical clustering analysis and principal component analysis, were performed on a broad set of nitrogen-containing curcuminoids. Compared to their respective mother structures, that is, curcumin and bisdemethoxycurcumin, all compounds, and especially the pyridin-3-yl -enaminone analogues, showed better water solubility profiles. Interestingly, the pyridine-, indole-, and pyrrole-based curcumin derivatives demonstrated improved biological effects in terms of mitochondrial activity impairment and protein content, in addition to comparable or decreased antioxidant properties. Overall, the biologically active N-alkyl -enaminone aza-aromatic curcuminoids were shown to offer a desirable balance between good solubility and significant bioactivity

Stomach temperature records reveal nursing behaviour and transition to solid food consumption in an unweaned mammal, the harbour seal pup (Phoca vitulina)

Knowledge of milk transfer from mother to offspring and early solid food ingestions in mammals allows for a greater understanding of the factors affecting transition to nutritional independence and pre-weaning growth and survival. Yet studies monitoring suckling behaviour have often relied on visual observations, which might not accurately represent milk intake. We assessed the use of stomach temperature telemetry to monitor suckling and foraging behaviour in free-ranging harbour seal (Phoca vitulina) pups during lactation. Stomach temperature declines were analysed using principal component and cluster analyses, as well as trials using simulated stomachs resulting in a precise classification of stomach temperature drops into milk, seawater and solid food ingestions. Seawater and solid food ingestions represented on average 15.361.6% [0-40.0%] and 0.760.2% [0-13.0%], respectively, of individual ingestions. Overall, 63.7% of milk ingestions occurred while the pups were in the water, of which 13.9% were preceded by seawater ingestion. The average time between subsequent ingestions was significantly less for seawater than for milk ingestions. These results suggest that seawater ingestion might represent collateral ingestion during aquatic suckling attempts. Alternatively, as solid food ingestions (n = 19) were observed among 7 pups, seawater ingestion could result from missed prey capture attempts. This study shows that some harbour seals start ingesting prey while still being nursed, indicating that weaning occurs more gradually than previously thought in this species. Stomach temperature telemetry represents a promising method to study suckling behaviour in wild mammals and transition to nutritional independence in various endotherm species

Synthesis of non‐symmetrical nitrogen‐containing curcuminoids in the pursuit of new anticancer candidates

Curcumin is known to display pronounced anticancer effects and a variety of other biological activities. However, the low bioavailability and fast metabolism of this molecule present an issue of concern with respect to its medicinal applications. To address this issue, structural modifications of the curcumin scaffold can be envisioned as a strategy to improve both the solubility and stability of this chemical entity, without compromising its biological activities. Previous work in our group targeted the synthesis of symmetrical azaheteroaromatic curcuminoids, which showed better solubility and cytotoxicity profiles compared to curcumin. In continuation of that work, we now focused on the synthesis of non-symmetrical nitrogen-containing curcuminoids bearing both a phenolic and an azaheteroaromatic moiety. In that way, we aimed to combine good solubility, antioxidant potential and cytotoxic properties into one molecule. Some derivatives were selected for further chemical modification of their rather labile beta-diketone scaffold to the corresponding pyrazole moiety. In this way, thirteen new non-symmetrical aza-aromatic curcuminoids and four pyrazolebased analogues were successfully synthesized in a yield of 11-69%. All newly synthesized analogues were evaluated for their antioxidant properties, reactive oxygen species (ROS) production, water solubility and anticancer activities. Several novel derivatives displayed good cytotoxicity profiles compared to curcumin, in combination with an improved water solubility and stability, and were thus identified as potential hit scaffolds for further optimization studies