Environmental reporting in Nigerian newspapers: a longitudinal study

Nature has endowed man with many resources that if properly harnessed, would enable him to live comfortably on the earth. Over the centuries, the use and abuse of these resources has led to their depletion. As the 21st century draws near, people have become more sensitive to the effects of a degraded environment on their lives. The main tool for this sensitization is information. This study is devoted to the coverage of environmental information in four nationally distributed newspapers in Nigeria. The newspapers were studied over a 10‐year period to ascertain the level of coverage. Analysis showed that the energy sector is the most reported of all environmental issue and that noise pollution is the least reported environmental category. Suggestions are made on how to improve the level of environmental awareness among Nigerians.     

Preparation of Co-Sn alloy film as negative electrode for lithium secondary batteries by pulse electrodeposition method

In order to easily and simply improve the cyclability of the Sn film negative electrode, we selected Co as a matrix metal and tried to prepare the Co-Sn alloy film negative electrode by a pulse electrodeposition method. The surface morphology of the deposit was almost the same as that of the Sn film, although aggregation partially occurred. The content rate of Co and Sn in the deposit was almost the same as the composition percentage in the electrodeposition bath. X-ray diffraction measurement showed that the deposited film could be assigned to a metastable Co-Sn alloy, while the co-deposition of crystalline Sn was not observed. The galvanostatic charge-discharge tests indicated that the discharge capacity and the charge-discharge efficiency of the Co_30.5Sn_69.5 alloy film electrode at the 1st cycle were 529.2 mAh g⁻¹ and 87.9%, respectively. Furthermore, the film electrode showed a good cyclability and discharge capacity of 470.5-617.5 mAh g⁻¹ during 50 cyclings. Alloying Sn with inactive Co could effectively improve the cyclability of the Sn film electrode prepared by the pulse electrodeposition method.     

Effect of mechanically alloyed sintering aid on sinterability of TiB2

High-melting-point borides are attractive for structural and functional materials used in extreme environments. However, their poor sinterability due to their high melting point and strong covalent bonding have prevented their further applications. In this study, a new sintering process, called transient liquid-phase diffusion sintering (TLPDS), has been developed for high-melting-point borides. TiB₂ compacts were fabricated by spark plasma sintering at 50 MPa for 15 min at temperatures of 1300 and 1600 °C via TLPDS of TiB₂ powder with a eutectic TiB–Ti powder as the sintering aid, prepared via mechanical alloying (MA). Differential scanning calorimetry results indicated that the melting temperature of the obtained sintering aid was lower than its equilibrium melting point. MA of the sintering aid suppressed the open pore fraction to one-third of that in the compact sintered with the aid prepared without MA when sintering at 1300 °C. We also propose a possible mechanism for TLPDS of TiB₂.     

Improvement of electrochemical characteristics of natural graphite negative electrode coated with polyacrylic acid in pure propylene carbonate electrolyte

In order to improve the negative electrode characteristics of a graphite electrode in a propylene carbonate (PC)-containing electrolyte, we have prepared a graphite negative electrode coated with a water-soluble anionic polymer as a binder for composite graphite electrodes. The electrochemical characteristics of the coated graphite were evaluated by cyclic voltammetry and charge–discharge cycle tests. The coated graphite negative electrode showed a stable Li⁺ ion intercalation/deintercalation reaction without the exfoliation of the graphene layers caused by the co-intercalation of the PC solvent in the LiClO₄/PC solution. The charge–discharge characteristic of the coated graphite negative electrode in a PC-containing electrolyte was almost the same as that in ethylene carbonate-based electrolyte.     

Electrochemical characteristics of Sn film prepared by pulse electrodeposition method as negative electrode for lithium secondary batteries

In order to improve the cyclability of Sn negative electrode, we tried preparing the Sn film negative electrode by a pulse electrodeposition. Based on the SEM observations, the crystal grains of the Sn film after the pulse electrodeposition were comparatively homogeneous and their grain size was ca. 1 μm. The discharge capacity and the charge–discharge efficiency at the 1st cycle were 679.3 mAh g⁻¹ and 93.0%, respectively. The charge–discharge tests indicated that the initial electrochemical characteristic of Sn film electrode prepared by a pulse electrodeposition was much better than that of the Sn film electrode prepared by a constant current electrodeposition. The GD-OES profile suggested that Li⁺ ions were easily extracted during the discharge reaction. In addition, it was found that no exfoliation of the film was observed after the 1st discharge though the cracking in the film was observed after the 1st discharge. Consequently, the Sn film electrode prepared by a pulse electrodeposition exhibited a better cyclability for the initial 10 cycles compared to the Sn film electrode prepared by a constant current electrodeposition. By reducing the particle size and repressing the morphological change, the initial electrochemical characteristics were considerably improved.     

A preliminary chlorine survey of the savanna soils of Nigeria

Chlorine contents of 32 surface soils representing the four savanna zones in Nigeria, the major soil parent materials and the main agricultural fields were examined. Total chlorine contents varied from 47.2 to 296.5 mg kg^-1 while the water-soluble chloride varied from 0.1 to 7.7 mg kg^-1 in all the soils. Total Cl and water-soluble Cl^- did not vary by either ecological zones or by soil parent material. However, according to the order of magnitude, the contents in the ecological zones may be arranged as follows: Southern Guinea > Sudan > Northern Guinea > Sahel while, with respect to parent material, the contents could be arranged as follows: Basement Complex > Basalt > Sedimentary > Aeolian. Preliminary results tend to indicate that over eighty percent of the Nigerian savanna soils may be deficient in Cl, though detailed study may be necessary. Lack of significant correlation between Cl and selected soil properties tends to indicate that neither texture, organic matter nor soil reaction has a controlling influence on Cl occurrence in the study area.     

Ready to Use Therapeutic Foods (RUTF) improves undernutrition among ART-treated, HIV-positive children in Dar es Salaam, Tanzania

ABSTRACT: BACKGROUND: HIV/AIDS is associated with an increased burden of undernutrition among children even under antiretroviral therapy (ART). To treat undernutrition, WHO endorsed the use of Ready to Use Therapeutic Foods (RUTF) that can reduce case fatality and undernutrition among ART-naive HIV-positive children. However, its effects are not studied among ART-treated, HIV-positive children. Therefore, we examined the association between RUTF use with underweight, wasting, and stunting statuses among ART-treated HIV-positive children in Dar es Salaam, Tanzania. METHODS: This cross-sectional study was conducted from September-October 2010. The target population was 219 ART-treated, HIV-positive children and the same number of their caregivers. We used questionnaires to measure socio-economic factors, food security, RUTF-use, and ART-duration. Our outcome variables were underweight, wasting, and stunting statuses. RESULTS: Of 219 ART-treated, HIV-positive children, 140 (63.9%) had received RUTF intervention prior to the interview. The percentages of underweight and wasting among non-RUTF-receivers were 12.4% and 16.5%; whereas those of RUTF-receivers were 3.0% (P = 0.006) and 2.8% (P = 0.001), respectively. RUTF-receivers were less likely to have underweight (Adjusted Odd Ratio (AOR) =0.19, CI: 0.04, 0.78), and wasting (AOR = 0.24, CI: 0.07, 0.81), compared to non RUTF-receivers. Among RUTF receivers, children treated for at least four months (n = 84) were less likely to have underweight (P = 0.049), wasting (P = 0.049) and stunting (P < 0.001). CONCLUSIONS: Among HIV-positive children under ART, the provision of RUTF for at least four months was associated with low proportions of undernutrition status. RUTF has a potential to improve undernutrition among HIV-positive children under ART in the clinical settings in Dar es Salaam, Tanzania.