1-D Transport Behaviour of Emerging Contaminants in the Unidirectional Flowing Surface Waters of the Msimbazi River

The primary objectives of this investigation of environmental pollution were to assess spatio-temporal concentrations and predictions of transport behaviour of pollutants in aqueous media. In order to attain these goals for the Msimbazi river, the analytical and numerical solutions to the 1-D advection-dispersion equation (ADE) implemented the first-type inlet condition. The MATLAB software was used to solve the analytical equation resulting from the ADE equation. The solution to the ADE model enabled effective prediction of contaminants’spatial distribution within a distance of 200 m from a point source in the direction of flowing water. Among the first and third-types inlet conditions, the first-type had the best exponential concentration prediction with descending concentration gradients between –100 ng/L.m and –0.4 ng/L.m, while beyond it the concentration gradient was merely constant. These findings are the first of this type in our region to the best of our knowledge, and hence a milestone for understanding the transport behaviour of emerging contaminants, and enable estimation of probable pollution-free zones. This study gave results that can form a basis for analytical and public interventions. Keywords: Modelling emerging contaminants; Advection-Dispersion Equation; Contaminants transport; First-type inlet condition; Concentration gradien

The effects of height and frequency of previous defoliation on nodulation, nitrogen fixation and regrowth of phasey bean

Inoculated seeds of phasey bean (Macroptilium lathyroides cv. Murray) were sown in a sand culture in a naturally-lit glasshouse, and imgated daily with nitrogen-Free nutrient solution. At early flowering, the plants were either left uncut or cut at node 5 (high) or node 1 (low), retaining the corresponding residual leaf areas of 74, 11 and Ocm 2 plant 1respectively. Following this initial cutting, new shoots were individually harvested at the frequency of one, two, three, four or eight times over a penriod of 56 days in Phase 1. Total dry weight of new shoots, seed yields and nitrogen concentrations in the herbage were assessed. A II plants were allowed to regrow during the next 21-day recovery period in Phase 2. Then, the root systems and plant tops were harvested. Nodulation,nitrogen fixation (total N) and regression analyses on s011Je plant parameters were computed. In Phase 1, cumulative yields of new shoots harvested following high or low-level cutting declined significantly with increasing harvesting frequency, but yield reductions due to low-level cutting were detected only under high harvesting frequencies. In Phase 2, recovery growth was always better following high than low-level cutting, but unexpectedly, the various harvesting frequencies had no effect on recovery growth following high cutting. After low-level cutting, high or low harvesting frequency reduced recovery growth compared with moderately frequent defoliation (two harvests in 56 days), which coincided with early flowering on the new top growth. Recovery growth had a positive linear correlation (r = 0.98 ***) with nitrogen fixation, which was also linearly correlated with nodulation. These results are briefly discussed with reference to the current concept that regrowth of nodulated forage legumes is largely dependent on symbiotic nitrogen fixation

Reflection Impacts Preservice Teachers Instruction and Planning

Access the online Pressbooks version of this article here. Creating a habit of reflective practice promotes ongoing and sustainable instructional improvement for preservice teachers. Furthermore, reflection enables teachers to strengthen their instruction through critical analysis of student learning and engagement. While reflection may be intuitive for an in-service teacher, preservice teachers need this experience to develop intentional and automatic reflective practice. Adopted from the field of medicine, Subjective, Observation, Assessment, Planning (SOAP) Notes is a reflective strategy that allows educators to critically reflect on the lessons they have taught. SOAP Notes promote critical reflection on planning and student learning and may impact classroom management and instructional decision-making

Reflection Impacts Preservice Teachers\u27 Instruction and Planning

Creating a habit of reflective practice promotes ongoing and sustainable instructional improvement for preservice teachers. Furthermore, reflection enables teachers to strengthen their instruction through critical analysis of student learning and engagement. While reflection may be intuitive for an in-service teacher, preservice teachers need this experience to develop intentional and automatic reflective practice. Adopted from the field of medicine, Subjective, Observation, Assessment, Planning (SOAP) Notes is a reflective strategy that allows educators to critically reflect on the lessons they have taught. SOAP Notes promote critical reflection on planning and student learning and may impact classroom management and instructional decision-making

Assessment of Soil Quality along the Proposed Main Road through Ngorongoro and Northern Serengeti, Tanzania

A new road through northern Serengeti National Park is proposed to be built. The purpose of this study was to collect baseline data on soils along the route of the proposed road before its construction. The physicochemical properties were used to characterize the soil before the construction of the proposed road. Levels of soil macro-elements mainly potassium (K), calcium (Ca), magnesium (Mg) and sodium (Na), and physicochemical properties: electrical conductivity (EC), pH, organic carbon (OC), soil organic matter (SOM), total nitrogen (TN), cation exchange capacity (CEC), phosphorus (P), aluminium (Al) were determined. Also, heavy metals: cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), lead (Pb), manganese (Mn), mercury (Hg), nickel (Ni) and zinc (Zn) were analyzed. This study was done on the eastern (Ngorongoro District) and western (Serengeti District) segments of the proposed road. The ranges in average values obtained for the physicochemical parameters and metal concentrations in the soils were: 0.05–0.57 mS/m for EC, 6.5–7.9 for pH, 0.71–1.23% for OC, 0.30–0.74 g/kg for TN, 1.23–2.12% for SOM, 20.6–79.7 mg/kg for available P, 0.27–2.08 meq/100-g for available K, 9.89–30.3 meq/100-g for available Ca, 0.29–0.67 meq/100-g for available Mg, 0.06–1.35 meq/100-g for available Na, 11.04–33.12 meq/100-g for CEC, 46702.9–63963.3 mg/kg for Al, BDL for Cd, 24.70–101.55 mg/kg for Cr, 27.31–34.96 mg/kg for Cu, 32390.8–42439 mg/kg for Fe, 18.06–22.19 mg/kg for Pb, 957.1–1458.9 mg/kg for Mn, BDL for Hg, 20.24–32.52 mg/kg for Ni and 96.09–124.14 mg/kg for Zn. These observed levels indicate that the soils before road construction are unpolluted, moderately fertile and within the specifications of good agricultural soil. On the western segment of the proposed road, the soil will need application of fertilizers for better agricultural usage. Keywords:    Physicochemical properties; soil quality; total nitrogen; macro-elements; heavy metals

RF Front End Receiver for WiMAX Application

This paper presents the design of a high gain, low noise direct conversion Radio frequency(RF) front-end receiver system. The Front end receiver is designed to operate at 5.8 GHz compliant with IEEE 802.16 WIiMAX standard. The system consists of a low noise amplifier (LNA), a radio frequency amplifier (RFA), a power divider and two band pass filters. The overall performance of the RF front-end receiver system produced a gain of 52.4 dB. A cascaded LNA designed for the system produced a high gain of 36.8 dB. The RFA contributed an extra gain 15.6dB. The overall noise figure achieved for the system is 3.7 dB. The return loss achieved is -25.5 dB for the RFA. The radio frequency bandwidth recorded for the system is above 1120 MHz. The measured power divider insertion loss is 2.80 dB. Using microstrip technology for designing the Chebyshev filter, the insertion loss is 3.00 dB and the channel bandwidth recorded is 107 MHz which can accommodate 4 sub channels IEEE WiMAX standard

Effects of Solution, Soil and Sand Cultures on Nodulation and Growth of Phasey Bean

Plants of phasey bean (Macroptilium lathyroides cv. Murray) were grown in nitrogen-free nutrient solution, sod, or sand culture in a naturally-Nt glasshouse. Nodulation, dry matter accumulation in plant parts, and seed yields were assessed. Partitioning of symbiotic nitrogen into various plant parts during vegetative and reproductive growth stages was also determined. In all culture media, nodule number and size increased with plant age but the rate of increase was generally greater in solution than in the other cultures. In sand culture, the dry weight per nodule and per plant, and plant growth were significantly suppressed. Although tap root elongation was consistently better in solution than soil or sand culture, leaf development and dry matter accumulation in roots and stems were enhanced by solution culture only during flowering and fruiting stage. Seed yields were significantly increased by solution culture, an effect apparently associated with increased symbiotic nitrogen fixation. During vegetative growth, nitrogen accumulated largely in the leaves and stems but pods were major sinks of nitrogen during the reproductive growth stage. The benefits and applications of solution culture in the study of nodule development and collection of root samples for acetylene reduction assays are discussed